Do i really need headers and injectors? help

Need some more info about your setup.
I am assuming it isn't the 5.0 in your sig.
Is the sc a series I, II, or IV?
Where are yo getting the kit? Since, unless they have changed things, the saleen kits don't come with a MAF.

Ok, that makes more sense. You can always add headers later, but they will definetly help. The Kit uses your stock MAF, so he is likely giving you an aftermarket Maf. What are you planning on doing for the tune? If you had bought the KIT new it would come with a box to ship your EEC back to Saleen to have it flashed. I suggest you get a custom tune though. If you want to run the LMAF and 42's you can have the tune set for them, but you are not likely to see much benefit from them, since you are not going to be making out the stock MAF and 30's that come with the KIT. With the smaller pulley the first thing you want to do is upgrade your fuel pump, or run a BAP. I run a BAP on mine with no issues.

there is one guy posting too you that has a sallen supercharger i would listen too him...

well for one no matter what supercharger you install a tune is needed..