Haha thanks, I will never go back that's for sure.
Invidia only make 1 system for the RCF, I believe they call it the Q300. Only a couple of us here in the UK have one as its imported from US. Well worth the wait.
So vs the QS I find it much more 'refined'. There is not drone or hum/vibration through the cabin like I found with the QS at low revs. The QS was awesome when driving it hard, but pottering around town started to grate on me to be honest. Especially when trying to go up a hill at 30/40mph, that went right through me.
The Invidia has the V8 burble as it drives past you at low revs, still makes people look - but its not AMG of course.
High revs it does scream, very raspy sound. Will bang/clap on quick gear changes and of course off the limiter too :-).
You will find the GT Haus quite a bit louder than that video of my Invidia.