wiw thanks guys i'v been looking in to PSI and have heard good things about them from most mustang guys and the LX cars but not alot about the vipers.... i'm going to have it tuned some where after the first of the year after i get my headers and a few more other do dads... i kinda want to get all the bolt ons i can before i have it tuned tho....so thats headers,TB, Magna flow cat back or custom 3" exhaust... and my nitrous...so i think it should make goopd numbers with all that stuff and a good tune