Well, ive just changed from a
mk3 Ibiza Cupra to mk4 FR TDI so i have got a fairly good comparison.
My old Mk3 was remapped and had a few other bits and was running around 210bhp with 230ish torque, the FR is remapped and has around 160bhp with 280ish torque.
The MK3 would eat my TDI FR alive, the petrol is a much faster car to drive as you have the accleration with the longer gear changes and it just keeps on pulling. I find the FR has the in gear acceleration but lacks the raw accleration to just keep on going.
If i could have i would have kept my mk3 but it cost me a small fortune to run on the amount of miles i do and i was just throwing money away when i could have the tdi and it still do everything i wanted and have the accleration to overtake and such. The TDI is quick enough, any quicker and i would think your an idiot doing those sort of speeds on public roads. The TDI has the perfect speed and accleration for what you would want on public roads.
For lots of miles and just day to day driving i think the Diesel is the far sensible option to go for.
If you want to do track days, sprints, 1/4 miles or seek huge bhp then the petrol is for you.