There is good sound, no sound, and then bad sound, in that order...
Lets assume you have a V8 with 180° headers, twin tailpipe and a six cyl twin tailpipe with 240° headers. If the bore & stroke plus all other factors ( head design, rod ratio, header size, induction etc ) are identical then the exh note of the V8 at 6000 rpm should be the same as six cyl at 8000rpm. Or simply 75% of 6 cyl RPM for V8.
As will the FGT market albeit maybe not to the same degree.I thought the XJ220 market died - not really a whole lot to do with the cars?
What if GM brings a midengine V8 Vette to market in 2018 for half what they're asking for the V6 FGT?
If you have enough cash laying around for a FGT why would you settle for 6 cyl when for the same money you could have 12?