Speed over 160km/h and GAS operation

Here I have a V70II (Bj 2003) with a front gas system (built by Volvo – system operator from Germany (Brillon)). This car got a system in 2008 and has this probably about 60-70Tkm in use. Current driving performance about 135Tkm. You get from all sides submissible hints and horror stories about the valves. Some say when higher power is required (WoWa operation or AB with 160 and more). The others: That’s all nonsense and d he motor (2,4) can do that already … and more. How are the experiences with this. I very much adhere to the specification …. but my predecessor, which it had built in?….. There were certainly 50-60T on his side. Experiences and advice? Gorden.