Doesn't it have that resonator/sound amplifier system from the intake through the cabin...? For some reasons I just assumed the Z4 sounded better than the Z3. (only recently the exhaust note studies have seriously developed)If you had a Z4 then any sound would be better than no sound that even the 3.0 have. I missed the little drone and burble of our old 3.0 Z3 that i had a scorpion exhaust fitted. Now our Z4 sounds just like our Z3 did