I have a XXX-S, TA04R and a TC3. I have raced all these cars with stock (27T 24 degree) motors, so I can directly compare them with a stock motor. My feelings are:
XXX-S The easiest to drive of the bunch. Very forgiving. Deceptively fast on the track.
Required hopups: front one-way, short front shock shafts, threaded shock bodies.
TA04R Looks the fastest on the track. Doesn't generate as much mechanical grip as the XXX-S, so it's the most difficult of the bunch to get set up. Fairly forgiving.
Required hopups: Lightweight diff outdrives, front one-way
TC3 Seems to generate more mechanical grip than the others. This car likes to be stiffly sprung. Not very forgiving. It is very twitchy unless you run it really stiff.
Required hopups: Many springrates. I suggest you buy the Factory Team spring kit since it includes the most used springrates. An extra rear shock tower to run up front, front one-way, 4 degree caster hub carriers, shock rebuild kit from GS. The shocks leak like a sieve with the kit orange o-rings.
The TC3 is better suited to modified motors, imo. I don't think it works very well with stock motors. I race mine in mod and I like it a lot. For stock, my choice is the XXX-S. The TA04R is for TCS