I am currently looking for a header for my 01 LS but I hear that if you put on just a header and not the catback there is a possibility that I might loose power. Is this true, is so should I get my catback first? thanks
You won't lose HP, but you are still running an incomplete exhaust system. Obviously, the stock cat and exhaust are not properly match for an aftermarket header so your exhaust system will not provide the gains that you would see with a properly match exhaust system.
If I were you Id probably get my cat back system, then go ahead and do the header =)You will get the best performance this way. As style stated, yes you would free up power from the header but since the rest of the cat and exhaust are the same its not going to provide a gain.