From what I remember when researching this when I was modding my typhoon, Bar and plate is better at cooling but doesnt let air flow though it as well as a tube and fin, this might be an issue in a front mount when doing a lot of beach work and restricting the radiator flow
The tube and fin type are usually cheaper and I think most of the time would be fine, Im running a plazmaman tube and fin in the typhoon its got over 440hp at the wheels and on track days in summer I havent noticed any heat soak effects, although its pretty big
Thats what I can remember anyway, others might have a better idea
2.5 inch piping is plenty unless you modify the inlet manifold. the hole in the top is only 60mm.
bar and plate vs tube and fin is a harder one. a GOOD bar and plate will flow more than a cheap tube and fin. I've seen tube and fin crack around the hot side piping.
if you have roiom for a big one go a cheap bar and plate, but make sure its been pressure tested