Lets talk caps

Im buying a R1PRO for racing, and some of the guys in the HK were saying there putting a 16V2200uf, and got more punch & response


So I was wondering, what cap should I use for racing thats on the small side? I need something pretty darn small, because its in a touring car, so rooms is very limited....

Can you guys help me out here? Or am I just wasting money by buying caps to race with? the speedo comes with a cap, and I will use this with a 10.5, and lipos....