I promised this ages ago, but it slipped my mind until just now. Nothing too in-depth, just a few words.
First thing I should note is that my old air filter was non standard, ruined, and sat right on the water pipe. Secondly, I don't tend to race or stress my car very much, so don't be expecting any 'redline' impressions.
After hassling Peter for about a month, or what seemed like a life time, my kit finally arrived. It was a little less aesthetically pleasing than I though it would be, a few slight imperfections in the material, but nothing major.
It is very high quality material though, and it's shaped perfectly to fit the car. The air filter on the other hand is quite large, no-brand model you can pick up on eBay for about £8. Not that this is an important factor, as your money goes into the bespoke pipe and design rather than the actual filter (which, as long as it's clean and large enough, is largely irrelevant).
Fitting was quite easy as it has a bracket attached to the bottom which is easily adjustable. It does get squeezed against the battery tray and the bonnet tends to press on it, but neither to any extent which would cause concern.
The first thing I noticed after fitting it to the car was the tone of the engine had become slightly lower and had an almost 'gurgling' sound (or as close as a four cylinder will get). Very pleasing. Secondly, the torque being produced, even at low RPM, was amazing. Caused a few unintentional wheel spins initially, a huge improvement. The engine felt more responsive, more powerful and much happier.
Lastly, was it worth the money? Well, it's a LOT of cash to spend on induction... However it does work and is quite an exclusive item, so it's difficult to give a straight answer. If pushed, I'd probably say 'yes', but it could always be a few quid cheaper.
I'm very pleased with the GSR kit - although I can only compare it to a worn, non standard unit, so please bear that in mind.
Please feel free to ask me any questions at all.