I don't think you'll hear any extra sounds with only the lower mount fitted - That's definitely how it is with the VWR mounts. But it's the lower mount which kills the vast majority of the engine rocking and delivers the power more directly.
You are aware im talking about the solid race mount not the fast road mounts that vwracing do right.
Herd it in Mat ed30 car and sounded mean, dont know if that was the blueflame tbe playing mind games and im pretty sure he only has the lower on fitted aswell.
Anyway aslong as it improves power delivery to the road and stops engine rocking im happy, the Grrrr is a bonus .
....I've driven one of VWR's track cars with solid mounts but there was so much glorious noise going on that I just enjoyed it a whole and didn't focus on exactly what each noise was. Otherwise, I haven't heard their solid race mounts yet.
Any Grrrr is definitely heard because of engine mounts and most definitely
NOT the exhaust. At first, on the VWR demo car aka Red Temptress, I thought it was exhaust too but that's only because you hear it in direct harmony as the throttle widens open.
Any Grrrr is a bonus, though not for everyone, and mine has remained the same since day1 and not lessened
We'll have to wait and see if the BSH behave differently or not in this respect. As they appear so similar to the VF I would expect the same behaviour.