£700? Are you hallucinating?
Uprated DV ~ £40
Installation - probably around 30 mins labour (but imagine you'll be charged one hour) ~ £60-80
Revo stage 1 - go to GTI international and get it done for no VAT. Works out to around £450 (or at least that's what I got mine done for last year).
So you're looking at aroud £550 for stage 1.
Personally, I'd recommend going to Stage 1 and then seeing how you feel. Most bang for your buck.
Edition 30/Pirelli - slight lower rev range lag and the power is really only shown at the higher rev ranges.
R32 - if you can afford the costs, but also £££ to make it go faster. ED30 will beat it in a straight line, though not round corners (esp if wet).