I have Short Ram intake and 5zigen fireball cat back exhaust. I am planning on ordering headers next week. I am thinking 4-2-1... but I am thinking about adding a 75 shot of NOS in the future, so wouldnt 4-1 be better or would it not really matter?
stainless steel 4-1 with a 2.5 in collector or a stainless, long primaries, hybrid 4-2-1 with a 2..5 in. collector would be good. A standard tri-Y would be choking her down...you need about 110% of intake flow through the exhaust system when you add N2O.
Of course when youre not using nitrous, you will not have nearly enough power to justify the extra flow capacity of that exhaust system. You need to decide if youre tuning your car for good everyday performance with nitrous as an add-on - or if youre tuning for best nitrous performance.