@ajp what setup do you have?
Do you mind writing a small bit about it, pros cons etc
I've got a Powervalve (aka BCS) turbo back, valved, R32 style, with 'R' tips, sport front silencer, 200 cell cat:
I had it fitted around February this year after getting the group buy going. I did lots of reading up before I made the decision and the more I researched things the more it stacked up in favour of BCS. One thing I kept hearing about 'another brand' was that some parts of the systems weren't stainless. And then the idea of an exhaust being quiet off boost and mad on boost appealed to me. I'm in my 30s, and it's a road car.
I'll list pros and cons rather than rambling. I may miss some stuff out but if you search some of my past posts I'm sure I've said plenty about it before.
Pros:
It's genuinely subtle and mature sounding off boost. If I'm in a situation where I don't want to draw attention to myself it's fine. I'd say off boost it's a touch louder than stock and a fair bit deeper, without sounding too boomy. It's a 'warm' tone (if you're into music in any way you'll know what I mean). If you lift off from partial throttle at low-mids revs it makes all sorts of lovely burbles and grumbles, but again in a good way. It's tasteful.
On boost and on full chat it's loud, and really howls. It's a noise I like to hear though; if it was loud and a crap tone it would have got on my t*ts by now, but it really is a gorgeous sound. I've run the exhaust on Stage 1, Stage 2, and Stage 2 with an uprated fuel pump, and every time the power has increased it seems to have brought a new characteristic out of the exhaust. Most recently I've noticed a nice pop between gear changes when I'm giving it the beans. I've actually removed my parcel shelf so I can hear more of the exhaust.
The 'R' tips follow the angle of the exhaust cutouts of an R32 rear bumper perfectly. It's a small detail but makes a huge difference. You can spec the more traditional R32 style tips which are slashed at a different angle (15 deg rather than 35), but for me the R tips look spot on.
Power and torque. As my earlier post explained, it just works. Massive increases across the revs. As soon as I set off home after having it fitted I noticed the turbo spooling earlier and the boost hitting harder. That was still on the Stage 1 map. My clutch started slipping before I'd even gone to Stage 2. It feels like getting a mini-remap.
Sport cat handles emissions with ease. Can't remember if it's in this thread or another but I posted up the emissions sheet from my last MOT.
3" all the way from turbo to just before the tailpipes. Some other systems go to 2.75" after the downpipe. I'm not in a position to categorically say what's better, but the power increase speaks for itself. The R32 style system in particular was apparently in development for 3 years, so in terms of flow and performance I'd say things are pretty much optimal.
No apparent disadvantage to opting for a the sport cat version rather than the decat version at k03 and k04 levels. I've researched lots of dyno graphs and I'm yet to see any evidence that either the sport cat or decat is any better than the other. The cat is made 'oversized' to ensure it flows as well as the decat.
Cons:
None really.
Some have argued that is at the higher end of things price wise. But it's not expensive for what it actually is. Compare it to any other variable-tone exhausts of the same quality and it's very good value. In fact, I can't think of any comparable exhausts. For me it's worth every penny and the best mod I've done. Powervalve will always be doing at least one group buy a year, and of course they're doing group buy prices on Black Friday this year.
Final note: I'm well aware that I can sound a bit of a fan boy when it comes to Powervalve. I can assure you I'm not getting paid for any stealth marketing. Although Nige, if you're reading this, giz a job! Joking aside, it's simply a damn good bit of kit and I'll sing the praises of any mod I feel is up to scratch, just the same R-Tech maps, H&R springs, the list goes on. I've had Milltek exhausts, Cobra, and so on, so I think I'm in a fair position to judge. If it was a sh*t exhaust I'd tell you. If it had faults I'd tell you. Bottom line - it's pure quality.