I got in trouble once because of a "modified exhaust" on my old SR5. It was a 2.25 inch straight pipe with a Apex'i GT Spec style muffler out the back. Sounded mad nice, just kinda loud. On my 4AG, I have a stock cat and a Flowmaster with no tip or muffler at the exit. Just a pipe (looks like ***, but I gonna do something nice with it). It's not too loud on the low end, but when my T-VIS hits, it gets loud. I am installing a test pipe soon because I am not crazy about the actual sound it makes, and also I need some power. But not all cops are on the look out for that. So don't worry too much.