Well they might not be the best, but I just made a hybrid that I was quite proud of.
A very simple one, but a great car for the game, especially since it's a pretty reasonable race car. (almost real world-ish)
A vertigo car base. Rgt engine. Rgt stage 4 turbo. 996 body.
The vertigo base actually fits almost perfectly... unfortunately, my rgt body didn't fit on right, so no rgt, but I still got the porsche, so that was cool.
Anyway, it worked out to have something like .9?? pwr, and .06 twr. Pretty powerful, but still within the limits of what the other really fast cars get to.
Anyway, I suggest to anyone looking for a great 996 hybrid, try building off of the vertigo, it works really well.
Oh yeah, if anyone knows a good base for a rgt race car, please let me know.