The Turbo XS is a nice exhaust, but it's still pretty loud. Make sure you get a cat on there. High flow is good, I've seen dyno results that show they make little difference if removed.
As far as getting hassled I know what you mean. In St. Louis where I grew up there was a van with the emissions testing unit in it. They used to take it to all the gathering spots for Mustangs. Back in the day everybody took the cats off their Mustangs including me. They would impound your car if it didn't have cats on it.
They also had a little device for measuring the tint on your windows. They would make you scrape it off on the spot.
BTW I have the Borla Hush with the twin tips and I think it's the perfect exhaust. I've left everything else stock. It sounds great, deep rumble without pissing anybody off.