Injector
 

What's the biggest injectors you can go before you have to change your injector pump ?

I would not go over a 50hp from stock.

x2 ^^ heard that numerous times

Depends on health of CP 3, which you need a gauge for, and what your goals are. My stock CP 3 can maintain 23,000 psi at extended full load WOT runs with 90's.