I had a Powerflow exhaust made for my mk2 gti and it cost approx 240quid. They are made on the spot so you need a couple of hours to spare for your car to go in. They are a nice tight fit and dont rattle around like some after market exhausts do. I am happy with the results and you can choose what finish you want on your rear box be it Single square, twin round, etc.
The one thing I would suggest is that your friend specifies she wants a quiet system. I went for a slightly louder system. The guy warned me that after time as the exhaust settles in it will get a bit louder. Well I have had the exhaust fitted for about a year and a half now and it sounds really nice on tickover but on the motorway it can get a bit noisy but i guess that is why stereos have a volume control to drown out the exhaust. I am going to go back to powerflow and get another rear box made up but a quieter one this time. I hope that is helpful
