30D Turbo, V8, V6 ... which one?

[Tymatk]

Hi all

I've never own an SUV before, i'm new to the scene and looking to purchase an X5, around 02-04 model.

I've been looking at the V8, simply because they're really affordable these days, luxury and the towing capacity but i'm a bit worry about fuel consumption.

Now i'm starting to look at the 3lt diesel, what are they like? Are they straight 6 or V6? Much less power than the V8? What's their off road capacity like? I don't really go off road but now that i'm buying a SUV 4WD, i'm thinking of going fishing somewhere far and remote but not really hardcore off road.
Please shed some light for a newbie

Thank you