are there any sound clips of one of these availablle?
....Not as yet, Glen.
The pre-production system I've got on at the moment has a 'noise' level which I would describe as inbetween their Resonated (quieter) and Non-Resonated systems.
My back box has "virtually nothing in it" Milltek inform me and consequently there is a resonator box otherwise it would be too loud for legal use - See pic below : -
Milltek expect to have a louder resonator section for us to try available from next week.
That's the background but to answer your question more directly, I'll have to ask Milltek about future sound clips. Meanwhile, if you PM stokeballoon who travelled about 1,200 miles with me to Nurburgring, he could tell you what my current "Resonated" Milltek sounds like. I'd describe it as audible all the time but only louder at higher revs. SteveP, TC, marky, Greenouse, would be able to comment on what it sounds like outside the car - Nothing like as loudly exciting as Greenouse's Milltek! (memories of the tunnels of Brussels!).
The other factor just to complicate things is that I now (since The Ring trip) have VWR Fast Road engine mounts and this contributes a wonderful
Grrrrrrrr!! into the sound mix under throttle, inside the car.