You've managed to hit a fair number of the "eternal debates"

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I'll be as brief as possible.
Edition 30:Standard: Faster and better spec'd than a standard GTI. Slower than an R32. Marginally more expensive to run than a GTI.
Tuned: Fastest car of the bunch. More BHP per £££ than the R32.
R32:Standard: 4WD (Haldex), NA 3.2l engine so good power delivery, fantastic noise but expensive to run.
Tuned: More £££ per BHP than a turbocharged car.
Mk5 GTI:Standard: Probably the sweetest of the bunch. Decent performance, subtle, cheaper.
Tuned: Map should see 240hp. Map, exhaust and intake should see 260bhp.
Mk6 GTI:Standard: "10%" better in most aspects than a Mk5 (interior, power, economy
Tuned: Maps pretty close to an Edition 30.
I had a Mk6 GTI. I mapped mine. I've gone back to a MINI only because I wanted something smaller again.