They balance out over the season depending on the track, so one car does not have a great advantage. The first season I thought RAC was stronger but an FZ50 won the championship. The second season I though the FZ50 had the advantage and an RAC won!
I'd say choose the car you like the most, I haven't really given the FZ50 a concerted effort because I love the RAC.
Once I've found a good setup I mostly stick to it for the season unless the track is very different (city). Setups are shared willingly, have a look through the posts of the previous seasons.
These cars can eat their tyres when sliding/drifting by mistake so the important thing is drive within their capablilities to ensure the tyres last the race.
Oh, and I haven't driven the RAC since.... last season
