I think the economics and bhp gains per £ spent start to diminish at some point though. When you think how much it costs to get to this kind of power, which is big turbo power on a 1.8T, on the scale of things, its quite cheap.
That being said, the cost to take off turbo, have it hybridised and re-installed, then go for another map to take advantage, its not cheap.
Also just how effective would WMI be? Possibly very effective, but nobody has done it yet on here or MK5 Golfs as far as I know, other than Dan, and I am not sure he has had back to back runs done with WMI running, and without. Even if he did, two subsequent runs can be so different - look at the runs on post 1 of this thread as an example.
Lightened pulleys may well work like a lightened flywheel with regard to reducing the work the engine has to do, but are lightened pulleys safe without the damping of the OEM set up? Decat is ok, but only if you are willing to buy a specific pipe or hack up a Milltek. Lightened 2 piece discs reduce rolling mass, but at the cost of several hundred notes, same as lighter seats, lighter wheels, lightened flywheel which makes lots of noise etc.
Being honest, I am really going to try and screw the cap on mods after this week as I dont think a few extra hp for a few hundred or a thousand notes here and there is going to be worthwhile in reality, especially on the road where my car will spend 99% of its time. After all, a standard
Cupra will keep up with the one in post 1 off the mark, and a remap only
Cupra will live with the car in post 1 up to approx 70-80mph which is as fast as you can legally go on the road. Only at that point will the extra power be noticeable. An extra 10-20bhp more again on to a
Cupra with all the bolt ons and 360bhp is really not going to make night and day difference to performance. A strict diet would be a much more effective option at making the car go faster (ie no back seats etc etc)