They're right, not much functionality in the quad tip exhaust, it's only for looks. The M cars have them but done necessarily need them. Dinan's M3 exhuast solution has 4 tips on it, but only 2 of them are functional. So on a cold morning, an M3 w/ a Dinan exhaust would only have smoke coming out of 2 pipes.
'06 M3 | Jet/Cinn | ZPP | Xenons | NAV | Military Sales.