GRP Titanium exhaust

[desertlotus]

Hello all. we have just Fitted a Gregs Race Parts Titanium exhaust to out 2020 Evora. We have found that, although at high rpm the exhaust sounds amazing and incredibly loud, at motorway speed 2-3000 rpm, there is a defining drone in the cabin. the car is basically full race sound all the time now. it is valved, but very little difference.

Has anyone here found the same issue and suggested fix?

thanks.

Evora titanium exhaust.HEIC ev tit exh 2.HEIC