Considering purchasing an ML, advice needed!

Hi all,

I usually hang out on the tech forum but I'm considering buying a a used ML, not sure of whether it will be a 320 or 430. I would like some expert opinions on what I should look for and which engine choice better suits the vehicle. Also typical gas mileage on the 320 and 430. Yesterday I found a 2001 ML 430 and a 2000 ML 320. Big difference in price but I'm really looking at the vehicle from a practicality standpoint, tire burning stop light drags are not a necessity (although that would be impressive for an AWD system).

Thanks in advance