Bought my '00 C4 Cab 5 months ago (without a Sports Exhaust fitted). Having heard a switchable system fitted to a 99 C2 Coupe, I decided I needed one. Problem: OPC price £2000ish fitted.
Had a look at aftermarket systems: Remus, Cargraphic, etc, but I had a bad experience with a Cargraphic system on a previous 2.7 Boxster. I had heard lots of good things about Fabspeed so looked at their website (http://www.fabspeed.com) - they've got excellent videos of the system in action. Ended up buying the 996 Maxflo Muffler system (with Fabspeed tips) and Cold Air Induction Kit (with BMC F1 air filter). Joe Fabiani (Fabspeed sales guy) was really helpful. All parts arrived by TNT within 4 days of ordering. The system is top notch quality and fit. I fitted the exhaust myself in an afternoon (only problem was rusty bolts on the system I was taking off). Cold air kit was a doddle to fit (30 mins max). With the exchange rate at $1.9=£1, the whole shooting match cost me just over £800. Not only that, on the rolling road, the car produced 318 bhp and 275 lbsft of torque (7% increase over standard). Incidentally, import duty was £18. Car sounds spectacular now. Cant wait for roof down weather and tunnels!! Only problem is the system isn't switchable so slightly noisy in towns etc (but not overly so).
If anyone wants more info, let me know.
Cheers for now,
Adrian Tillin.