Hi there, here's my quick opinion.
Go for the Gti.
The Gti is cheaper to run and more tuneable. With a few minor mods the Gti can make the same power plus it's lighter.
The R32 is 4 wheel drive so better traction. The V6 engine sounds awesome especially with a good aftermarket exhaust. Supercharge or Turbo the R and it would be awesome. As you would guess very expensive to tune to make decent power gains.
Have you considered a mk5 Edition 30 Gti? You should as that is without doubt the one to buy IMO. Better engine, more power, nice extra styling mods and far more tuneable to make big power.
However, if you're looking for cost effective ownership then again buy a standard manual Gti.
Mileage isn't a major issue on these cars so more importantly look out for a properly serviced and maintained car. Look for detailed service history etc. There's plenty of these cars out there so take your time when choosing.
All of the above are great reliable cars. Do a search on the forum for common faults as there can be a few and they have been covered numerous times. Gti's - coil packs, diverter valves, pcv's, front wing corrosion etc.
With the DSG box again look to see servicing. The oil for the box should have been changed every 40k. I have read there can be issues with the DSG box.
Hope this helps.
