Got all the RUFs now. They've all got pros & cons, but have to say that i'm not all that fussed about the 3400
CTR Yellowbird (RWD): This is THE beast to be tamed in the game. Forget the X1 lol, if you can manage a sub 8min lap in an unmodified one of these with comfort hards, then you must be a good driver

Keep this one standard and just buy a nice selection of tires to hoon about it. When you drive this car, just do it for fun and satisfaction - don't expect to be able to race this thing with any success!!!
CTR2 (4WD): Not my cup of tea. Have tweaked it with a new center diff and LSD but it just won't behave how I want. Will probably come back to this one as i've heard that it has potential with some tweaking - although i'm having too much fun in the others to be motivated yet!
BTR: Best of the bunch IMO. Bit more grip than the yellowbird and more predictable handling. Very satisfying to drive and IMHO the best of the RUFs. I ended up boosting the power to about 480bhp, lightened right it up and added a rear wing. Suspension is the same from what I remember. The thing is so sublime to drive now. The car puts down the extra power without sacrificing the original handling characteristics at low speeds. At high speeds I can now also drift more successfully due to the wing... anyone want the full setup, i'm happy to share - i may have also tweeked suspension, can't remember now
RGT: This is what I expected the RUF cars to handle like before I'd driven any of them. It's got much more grip than any of the others and can be drifted and driven normally with a fair amount of precision and predictability. Great car to initiate your new RUF obsession with

I have just boosted power on mine
3400: only driven it a couple of times, but it just didn't feel very porche like. Ended up modding the fook out of it to make it better but not found the best balance yet... probably gonna write this one off as a waste of time, unless anyone thinks they know a good mod formula for it
Cheers
Sunil