My father has had a kreissieg F1 exhaust fitted on a 2004 360 spider for a year now. I can't understand your post because the valve open position happens automatically once you have hit about 3200rpm. there's no choice except to have the full deal sound at this point. The remote control unit only allows you to select quiet mode which softens the sound down untill you hit 3200 rpm. So the only place in the rev range that is alright except for track use is 1000 - 3200 rpm according to you.
Brendan, you are right in what you are saying - as am I.
That's the trouble with posting text sometimes, it can be read two or more ways. Put simply - it's too loud with valves open under 3800 rpm - way too loud. I hope that clears it up.
Mine accidently opened (?) in the tunnel over the weekend and I think my ears are still bleeding.
It puts the lotion on its skin, or it gets the hose again.