It's usually hard to have two different cars in one; the best solution is to have two vehicles (cutouts may be a cheaper solution).
Most of the responses I've read who are "loud exhasut happy" don't have real loud cars on the highway daily. It's nice for a car that you choose when you drive it, but sometimes sucks when you get a headache from it. Setting off car alarms is fun too, but I got tired of that as well.
Ah...what am I saying...my truck is loud too, but not obnoxious.