Used X5 buying advice

[Getsideways]

Hello this is my first post here, and I was hoping that some of you current x5 owners could shed a little light on a few things for me.

With the dramatic drop in prices recently I have decided to hop into a nice suv. I am young, work hard, and don't have alot of money but enough to get into something between 15-28k. i would love to steal something for under 20k right now, but would spend a few extra bucks to get something real nice. I am looking at both BMW X5 4.4's and Jeep Grand Cherokee srt-8's. I have seen srt8's as low as 25k w pretty low mileage (20-40k) and X5's as low as 15k with decent mileage on them (50-80k). I currenty drive an sti and am looking to upgrade to something that is a bit of a better daily driver for the NYC area with all the traffic and pot holes. I love fast sporty cars, which is why the srt-8 and x5 has made the list.

Ideally I would like one with the sports package. However, I can't find any real info on the suspension differences between the 4.4i and 4.4is. I would also consider a 4.6is but they are a little harder to find. Can anyone tell me what the major suspension differences are, besides the sport suspension just being stiffer? I cannot afford a X5 4.8, so for this discussion we can omit any changes or differences for that model.

In addition, are there any big problems to look out for when purchasing these used? Certain years or options to stay away from or be leary of? At what amount of miles do I need to replace lots of expensive stuff at (timing belt, cv/axle crap, pumps?) I would assume the 2000-2001 models were a little bit more problematic. Any insight would be greatly appreciated!

A few recent deals I saw that caught my eye and I went and test drove but didnt pull the trigger:

2002 4.4i w/ 48k silver on black, one or two small dings that could easily be removed. Car drove and looked fine. Had bubbling paint on painted area on top of the motor. Rear trunk lid did not sit as flush when closed on the passenger side as it did on the drivers side (indicating either an accident, or repeated attempts to slam trunk shut with something stuck in the back ???). Clean carfax. Needed tires. I got the guy down to 15k, and then walked away....

Any lovers or hater of the cherokee out there>?

2001 4.4i 69,800mi silver on gray w the 20inch 5 star sport rims. Visually the car was good, and drove well too. Clean carfax. Got the dealer down to --15.5k and walked away.....

2002 4.4is 67k Blu on gray, sport package, nav, and a few other things. Body is clean, but I have not test driven it yet. Dealer is asking --14.7k

2007 Jeep GC Srt8 26k black on black, nav, sunroof, etc, warranty --25k