What is the difference between a 2007 or 2008 BMW 528 i or xi?

I am in the market for a new car and I am interested in a 2007 or 2008 BMW 528 but I am unsure if I want 2007 or 2008 i or xi? Can anyone tell me the difference between the 2007 or 2008 i or xi? The pros and cons?What is the difference between a 2007 or 2008 BMW 528 i or xi?BMW uses 'i' to indicate that the model has a petroleum engine under the hood as opposed to 'd' for diesel (the 'td' abbreviation is common since it stands for 'turbo diesel' which are a common pair.) 'x' is used by BMW to note the presence of their 4-wheel drive system. The pros are that in performance vehicles, a 4WD can further enhance the vehicle's ability to go 'round corners and its overall stability. The downside however is that it will add weight to the vehicle, and the steering feel can feel somewhat awkward and sluggish if you're used to a RWD. A real comparison would be between a 2008 and the 2009, that's when the BMW lineup received a major face lift and a thoroughly revised interior, something to bear in mind if you're comparing aesthetic values. And with all that improvement to cosmetics, I'm sure they've noticeably upped the engine's capabilities as well. I greatly doubt there's any notable differences between the 2007 and 2008 models though so I suggest your choice be chiefly driven by weather or not you'd want a 4WD Bimmer.