Mine has one on which was there when I got car. Seems ok, quite easy on the ears. Not a fan of double outlet back-boxes on the 172 though, so Nw perf are gonna look at turning mine into a stealth when I'm there for belts on Thursday.
Tbh mate I think a lot of peeps with Millteks have had issues with the welds on Rs cars, which is strange as there held in very high regard in VW circles. Think tbh there's a lot better systems both stealth and exposed depending what you want.I'm just adapting mine as car is just a toy, so working with what I've got...