id suggest taking it to any midas or other muffler shop and they can straight pipe the thing, put in bigger piping all the way thru, install whatever muffler u want, get rid of or add resignators, a cat back system like those u mentioned are good but overpriced and in my idea not worth it, i had a whole new mandrel bent system put on my car with labor running right around 200 bucks, spent 100 on a stainless steel magnaflow muffler and i like it alot, nice deep sound.