A while ago I had a nice Tanabe cat-back on my Civic. Well, I was cut off and it was totalled but while it sat in the lot for a month (while I waited for my cash) I took off the pipes and they seemed a bit coroded. Lots of chips and debris came out of the pipes and the resonator was rusted over. I was thinking of just getting new piping and a resonator fabbed up to my old muffler. My question is, do you think this corrosion that hit my pipes effected my muffler? It looks the same on the outside but I don't know if it's still in good working order. I don't want to spend $200 for new pipes and a resonator when the muffler is no good. Thanks for any input.