In defence of the K04 and, as someone who has gone K03 to K04, I think the decision is very much a personal one based on what journeys are usually done and driving style.
I'm not all out to defend going K04 however as there are some very valid points - it is laggier that the K03 of course (although the idea of the K03 being spooled up by 1750 rpm and the K04 kicking in from 3000 rpm is misleading!), the point about a lot of power being available in the licence-losing area is very true and the cost is certainly true. I can completely understand that for the day to day driving for some folks, a K04 would not be very beneficial, if at all, and would be a waste of a lot of money.
On saying that, I was surprised at how the K04 lag vs. increased power made the car very well behaved under normal driving conditions if that makes sense
- general driving around and pulling away from junctions still has plenty of power but is in no way punishing...drop it down a gear, get in the rev range of the turbo and put the foot down and it's real Jeckyl and Hyde - the power is nuts! There is still a flip-side to that though - controlling the car is a bit more of a handful and getting the power down can be an issue (I'll be getting better tyres in future and a Quaife next week for that reason!). I may have to keep the revs up and work the gears a bit more but I would usually leave a standard or remapped K03 car behind me....although not as far behind as I would like
Finally, I cheated a bit - I bought a 57 plate Octavia VRS 2 years ago with 15k on the clock at a very nice price and, even with the mods, think I must be quids in over an S3, Ed30, etc with the same age/miles...not sure about a Cupra though.
has anyone ever just considered putting the k04 turbo, injectors and DV relocation on as the first mod. with a map that would give you 280-300hp.
If the remap costs you £600, turbo costs you £800, the DV relocation £200 and the injectors £200 that would still be cheaper than going stage 2+ on the k03 turbo with stage 2+ remap, TBE, Intercooler, HPFP, and discharge pipes.
then at a later date you could add the exhaust and intake etc
If I could do it all again knowing what I know now and recognising the cost of going up stage by stage, I think I would consider this option Sy but only after handling mods like brakes, ARB and probably suspension