benifit - none
downside - your car will run rich.
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bigger injectors no good unless you have the ecu to tune them.
not sure on how knowledge on how an injector works, but an injector is just an electrically opperated tap. the ecu sends a pulse of electricity (well..it grounds it) to the injector (in milliseconds, so at idle the pulse may be 10ms, and at full steam it may be 90ms, dont quote those numbers). and when the injector gets the pulse the solenoid opens up the little tap and lets some fuel into your engine.
now if you go ahead and put in a bigger tap (ie bigger injector) then when the injector opens for said 10ms or 90ms, the only difference is gonna be more fuel going in....
pluss its only an extra 15cc, hardly worth it anyway. from what i understand stocko injectors are pretty much on the limit for 4age, but they are fine for a standard engine. if you were going to get a set of camshafts, and inprove your intake (porting, quads etc) then a bigger set of injectors would be needed to supply the fuel to burn with all the extra air you can use, but you would need an aftermarket ecu to control them anyway.
if the engine is running well now, dont touch it!
ps. your signature pic is cool!