Hello, I have 2 golf mk2. A 1.6 TD and the other a 1.8 GTI. For amount of kilometers, I remain without a doubt with the diesel. By force, good response both on the road and in city, to advance and others, because undoubtedly gasoline. If you look at the economic part, then I fill the deposit 1 or 2 times a month, while GTI 2 or rather 3. In my opinion, I think it depends on the use you are going to give. Many kiloḿetros per month, because diesel. No, then gasoline.
I don't know if I clarify something, or I put you in more doubts, hehehehe.