ok i bought this racing beat turbo back system for my 88 tII which was supposedly new..but it obviously wasnt since it had rust. the guy said it was sitting out in his garage for a while and got rust on the outside..i just used steel wool to get as much of it off as i could on the outside.. i got off all the orange but there was still some rust spots..i coulnt get it off lik to whre it was pure clean metal. should i worry about this? will it still eat away? after i steel wooled it i sprayed it with high temp paint to ensure not more rust. when i letting it dry i notced that there was also some rust inside the piping leading to the muffler. im pretty sure it is not the same rust as the outside.. but should i worry about it? is there anything i can use to clean it off? thanks