I had a catback magnex fitted to a new MINI Cooper that I bought in 2002 it could be quite drony at certain revs on the motorway.

Great for burbles

When paired with a pipercross cone air filter it sounded awesome - possibly even saw a very small increase in BHP so make sure you declare it to your insurance company.

I think the exhaust comes with a lifetime warranty (for as long as you own the car).