ok, so I drive an 04 tibby for those of you who don't know. a guy on the forum is selling a set of headers, SSA ver.1 for 100 bucks. he lives near me and said we could meet halfway. he says there was just a minor fitment issue with the front crossmember that could be fixed with a little dent in it. he said the headers were on the car and worked great with no leaks. now here are my questions....

I do not have anything done to my car yet, but bc this is such a great deal I was wondering...how much gains would I see with intake and headers, and stock exhaust with no cat?

second, after i got the headers and intake on, my shop down here said he would do custom mandrel bent piping for me for like, 100 bucks. now if I were to leave the stock mufflers on the car, would that hurt my performance at all? would I need to buy aftermarket mufflers to see the full gains? and are there any other issues ya'll would foresee with putting on headers first before anything else? oh, and just so ya'll know, my family moved to augusta, so I do not need emissions anymore.

thanks in advance