I made HP [email protected] and TQ 254 @ 4200. But the MAF and Injectors aren't being overworked with the NO2. The stock MAF and injectors will sork fine with any NA motor unless you want ot swtich to race fuel, go to 14:1 compression, some KENT stage 3 cams, serious head work, etc.. or want to make some big HP on E-85 fuel.
I think I heard the stock fuel injectors were good for about 145-150 wheel horse power. Im pretty sure that is right. So when you run out of leway with the 19lb injectors and switch to a larger lb, you would have to either recalibrate your maf or go with a pro-m or something along those line. I picked up some svt-f injectors (30lb) and I am going to just by a used maf somewhere to fix my problems