I've ran a CR prototype all season with fairly good results.. E finaled a national with it, kept my F2 with it and Tq'd and won a regional for the first time. My all time best results so far
The car is VERY good it has to be said, but it's down to what you prefer.
You can set the car up as much as you want, or as little as you want. I made a nice 'general' setup i used for the start of each meeting and tweaked a little to dial the car to the conditions. The car is very good over the bumps, a great flyer and the rear end stays planted all the time.
The downfall of the CR I found was when the conditions get wet, the little lack of steering the car natually gives shows an awful lot with the front end pushing though the corners, mostly on the astro. This can be resolved with set up changes, but the B4 is definatly the dominant car when the rain comes.
Ive just got ahold of a B4 again after having the opportunity to have some help from other racers (of who i very much appreciate), and with the help I received the car was very good, my old b4 seemed to be very random, especially the rear end. But with the set up on now, the car seems to be dialed, it has the extra steering the losi slightly lacked which i could use to my advantage from the extra experience from the past seasons.
Sunday was a VERY random day, the track started off damp, dried up then we had torrential rain. And ive got to say the car was great in all the conditions - even when the bad downpour started the car still gripped.. on yellows ! but after the rain stopped and the track was just damp there was a distinct lack of rear end grip.. nothing else i could of expected after that much rain!
Both cars are very competitive, and you can do well with either.. the Losi is very forgiving and will get you a good time over 5 minutes, wheras the B4 will give you the fastest times over one lap and requires a good driver to keep them laptimes over 5 minutes.
If you have any questions i will try answer them as i like to think i've experienced alot from both cars.