Firstly, drive both of them, preferably back to back and as aforementioned, on similar roads.
Remaps are an option on all three cars although proportionally you will see greater gains on the petrol engines.
You will love the power of the petrol engines and how you get off the line, it's addictive and when you take it up to the redline you discover.... oh my, there's a torque spike hehe (well on my cupra anyway).
However put your foot down in gear on the motorway in the diesel and you will grin. (and that's from memory with my old 150 TDi).
So you need to do some serious thinking. Weigh up how much motorway pounding you do against how much fun you will have on shorter stretches where the acceleration of the petrol will be more noticeable.
Bottom line is, my commute is 2 miles each way and I still drive a cupra because even around those roads I put my foot down and have a laugh. (or is it for the street cred I get from the kids I teach....)
Anywho, back to marking A levels and deciding peoples' futures. Mwahahahaha, the power