I have one, VERY quiet indeed, I never had a standard system but this must be very simular. I got rid of my loud system as it was doing my head in on A roads, this is much more bareable.
Price is obviously good, the midbox is huge though and compared with my other system and hits on everything. The fitment is again ok but my previous system was much better, from the midbox back the pipe sits quite far below the heatshield, also the backbox is huge and sits at abit of a strange angle nearer the middle of the bumper than my last, but bearable. Also the U bend over the rear beam isnt that huge so mine bangs now and then. It took 6 weeks to reach me, even though every week when I rung up I was told "next week", and finally I was told it was always going to take that long...great company.
All in all, its an ok replacement for standard that doesnt fit great and took (for me) forever to arrive, from a company that constantly gave me incorrect dates for delivery. But for just over £200 posted with Cliosport discount its good for the price, would defo get one over a standard Renault system. It does still have a very subtle groan which is nice but obviously ive lost probably all of 2bhp from it over my stainless system, BUT ive lost a shed load of annoying boom on motorways.
Ill get some under car pics when its not pissing it down!