First of all, you should head on to one of the nearest car saloons, however you might consider saving up money for later. After you're done with Ronnie, the game will unlock two best vehicles of the game. Like I've said before, they will be very expensive to buy and upgrade.
Lamborghini Murcielago (#1) is like a better Gallardo. I think it's the shortest possible description for this car. There are some major differences, though. First of all, Murcielago is much faster than the Gallardo. The car handles very well, however you would have to spend a lot of money into the performance upgrades. I'd personally recommend staying with one of the "older" cars. The only exception would be if you had wanted to switch the Gallardo to something similar, but slightly better.
Ford GT (#2) is one of the biggest disappointments of the game, at least in my personal opinion. First of all, the car handles horribly. You will probably notice that while going through series of faster corners. You will lose a lot of time during these moments. Nonetheless, the car has some advantages. GT is very powerful, so you wouldn't have any problems during challenges with a lot of straight lines. The main thing is that these type of races aren't that common during the Career mode. As a result, you might as well forget about this Ford, especially since the better Murcielago is a lot cheaper.
Ronnie will require you to accomplish eight instead of seven races. Here's the list:
1) Races won: 8
2) Milestones completed: 5
3) Total number of points: 5550000+.
1. Sprint - Seagate & Camden
The first part of this challenge is not that hard. You should remember this track from the previous races. Use the right shortcut once you've left the main tunnel. Watch out for the tight right turn, though (#1). You will have to use your brakes quite aggressively. You will be encountering a lot of interesting shortcuts along the way (#2). It would be best to use them. The only exception are the very tight turns. In that case, I'd recommend staying on the main road. Use the nitro to help you out in difficult moments.
2. Lap Knockout - Riverside
You should reach a small junction that's located near the start line. Choose the path located on your left. The next decisions won't be that important, so you don't have to worry about them too much. Remember to use all visible shortcuts along the way (#1). Don't forget about the possibility of activating nitro, either. You should reach the sewers within a few seconds. It's probably your first time here, so you have to be very careful. Don't hit any of the pillars!! You might also consider using the left shortcut (#2). It should help you to keep the lead.
Watch out for a very challenging right corner (#1). It's been located near the sewers exit. Use the nitro to help you out in more difficult moments. You will have to deal with several tight corners near the end of the lap (#2). Thankfully, you should be able to cut through most of them. Don't forget about your opponents. You might consider blocking their movements at this point of the race.
3. Tollbooth - Petersburg Projects
This challenge is a very easy one. You shouldn't have any problems with it. There's a long stretch after the start. You have to be careful, though. There's a challenging jump over here. Thankfully, you don't have to slow down (#1). Get ready for the upcoming corners. You should know this segment of the track very well. Thankfully, the corners are very fast, so you should be able to maintain a rather high speed. Watch out for the local police forces. They will start the pursuit very soon. You will have to make a sudden left turn just before the finish line (#2).
4. Sprint - Bond & Forest Green
First of all, you will have to go through a long tunnel. Use the brakes once you leave it, because there are some challenging corners nearby (#1). You won't be allowed to make any mistakes. Otherwise, you would have lost your lead. More corners have been located nearby, however if you've got a car with good handling abilities you shouldn't worry about them at all. The final part of this challenge is by far the most challenging one. You will be driving on a freeway (#2). Avoid the nearby trees at all costs. Warning! If the opponents have faster cars try returning to the main menu and restarting the challenge from there. If you're lucky, they will be "awarded" with slower vehicles. Thanks to that, you should be able to win this race without any problems.
5. Speedtrap - Masterson & Route 55
You shouldn't have any major problems with this challenge... that is, if you've managed to win these type of races before. Most of the speed cameras have been located near some mild corners (#1). Try to pick a best possible route. Thanks to that, you will be driving with higher overall speed. Don't forget about the possibility of using nitro! You will be encountering more challenging turns along the way (#2), however you don't have to worry about them too much.
6. Tollbooth - Petersburg & Project
Pick the left path once you've reached the first junction. Sadly, you won't be able to accelerate too much, because there's a challenging turn nearby (#1). You must go past it without any problems. More junctions have been located nearby. In most of the cases, both paths will lead to the same conclusion. Be sure to use shortcuts along the way. You will also be able to cut through most of the corners. Once you've reached the industrial district you will be presented with a series of very challenging turns (#2).
7. Tollbooth- Wharf & North Bay
Use the tunnel located beneath the lighthouse. Even if you hit one of the surrounding barriers you will have an opportunity to restart the race without losing too much time. Watch out for a very challenging left turn (#1). More corners have been located nearby. Be sure to break through metal gates in order to get to the lower platforms. Once you've reached the refinery use the left shortcut. You will come across a new junction in a few seconds. Head on to the right path (#2). Choose the narrow road located near the exit of the nearby tunnel.
8. Sprint - Hwy 99 & Projects
It's a very simple race, really... mostly because that you should know this track very well. Use the prison platforms that have been located near the start line (#1). Thanks to that, you should be able to maintain a rather comfortable lead. Watch out for some tight turns, though (#2). You will have to deal with them in a few seconds. Thankfully, the final segments of this track aren't too complicated. Once you've reached the industrial district use a couple of surrounding shortcuts in order to maintain the lead.
1. Trade Paint (140000 points)
It's a rather difficult challenge. You will have to make contact with at least 32 police vehicles. I guess I don't have to remind, that you should try advancing the pursuit to one of the higher levels. I'd recommend hitting smaller roadblocks and staying on the freeways all the time.
2. Bounty (140000 points)
This is by far one of the most difficult milestones of the Career mode. You will have to collect 600000 Bounty points during a single pursuit!! Remember about the possibility of activating additional combos. If you're not that comfortable with these pursuits you might consider completing all of the photo tickets instead.
3. Pursuit Evasion (140000 points)
This is a very easy challenge. I'd recommend choosing in from the garage menu. Thanks to that, you should be able to immobilize or lose surrounding police vehicles quite easily. You must do it within a two minute time limit.
4. Pursuit Time Challenge (140000 points)
This time you will have to maintain a pursuit for at least nine minutes. It shouldn't be much of a problem, especially since you're trying to accomplish at least two other goals.
5. Photo Ticket (94000 points)
You can choose between three different milestones. Thankfully, you won't have to be driving at insane speeds in order to accomplish these challenges. A fully tuned vehicle will do just fine.
You will have to win two Circuit races and a Sprint in order to defeat Ronnie. The races aren't too hard, however you will have to spend a lot of time with them, mostly because of the long Circuit challenges.
1. Circuit - Bay Bridge
This isn't a hard challenge, mostly because you will have an opportunity to extend your lead near the end of each lap. Once you've started make a right turn and use the nitro. You will have to go through several difficult corners (#1). Don't worry about the surrounding objects. You must only avoid pillars and buildings. You should reach a very well known sectors of the map very soon. Be careful, though. There's a tricky turn located at the end of a long stretch (#2). You can't afford making any mistakes.
Once you've reached the end of the tunnel choose the path located on your right. The final part of the lap will require you to go through a narrow passage. After that, you will have an opportunity to make a small jump. Use the brakes aggressively (#1). Make a right turn and use the nitro again (#2). Thanks to that, you should be able to reach the finish line with a very comfortable lead.
2. Sprint - Seaside & Lennox
First of all, you will have to deal with several mild corners. You should be able to cut through most of them without any problems. Watch out for some narrow corners (#1). They will begin to appear shortly. Don't forget about the possibility of using nitro. The final part is going to be a lot harder, mostly because you will have to go through a very tricky right turn (#2). It would be a good idea to activate the Speedbreaker feature, especially since your opponent will probably be close to taking the lead away from you.
3. Circuit - Camden Tunnel
This track should remind you of one of the previous races. The main difference is that this time you will be driving in an opposite direction. You will have an opportunity to make a huge jump after the start (#1). Once you're on the ground use the brakes in order to get past a nearby turn. You should reach a small passage leading to a tunnel. Be careful, because your opponent will probably speed up. Don't worry about it, because you'll able to hit his car at the other end of the tunnel (#2).
The final part of the lap is very simple. You will be encountering several tight corners (#1), however you should be able to cut through most of them.
You might want to consider winning Ronnie's Aston Martin DB9. Just as before, you will probably sell it, because it won't be of any use to you, especially since the following races will require having a very powerful car.