I had the same issue with my car. I started getting tired of smelling like the car after driving it and having it stink at stop lights etc. It's a common problem if you have deleted your egr setup. I don't like the egr but It helps decrease the combustion temp and in turn reduces the nasties like NoX gasses etc. I ended up buying 2 of the magnaflow high-flow metallic spun cats. I hacked up my bbk h pipe and welded them in. I have hardly noticed a change in tone and no obvious decrease in power. The smell is not 100% gone but is noticeably better. I think they were about $90 ea. it's important to choose ones that do or do not need the air injection. I removed all my smog assembly so I had to get the 3-way catalyst ones that do not require the additional air to operate. Make sure your A/F ratio is close, cats won't live long in a rich condition for long.