Technically it's a violation of federal law to modify the emissions equipment on every car; the issue is some places like Phx and LA actually check. I could register it outside of Maricopa county, but I am actually trying to do this legally. It will be worth a lot more someday if it was legal. Hey wait a minute... What am I talking about? S-10's are dirt cheap. I could register in flagstaff, drive the wheels off it, then yank my 6.5 and throw the rest away. Just kidding, im still going to try do to it legally.