Trying to help out a friend to decide on a "gently used" AWD bimmer. He's thinking about selling his e39 530i to fund a 5 or 3 series AWD bimmer...I'm trying to talk him out of selling what is perhaps the best balanced bimmer with a timeless design, but I think I will fail. My suggestion was to go with 06-07 328xi, since that will given him a good car with some warrantee for a couple of years, but not sure how the E46 AWD cars have served their owners over the years. I personally also like the way the E53 X5s drive and look, but my friend's not the SUV type. Any opinion would help, so thanks in advance.
Some thoughts... I wouldn't get a 2006 3 series sedan as it's the first year of the e90 body style. They have problems that are to be expected in a first year model, but are otherwise pretty reliable. All of the AWD cars tend to have issues with the front axle cv boots tearing, inners and outers. These are not cheap to replace (approx. 400-500 depending on where you live) and will probably need replaced every 50-60,000 miles. They should be checked before you even consider buying a car. Many people decline the repair due to the cost to replace $30 worth of parts, but then the axle joint fails and can require axle replacement which is more than double the cost to replace the boot. Both the e46 3 series and the e53 X5's have window regulator issues. You will replace at least one of them if you own the car more than 25,000 miles. Run all the windows up and down and listen for any cracking noises. Also make sure the one touch operation works and the windows aren't moving very slowly. Try to take the oil cap off with the car running. If it's hard to get off you could have excessive internal vacuum due to crankcase vent valve failure. This is more common in states with cold weather in the winters. Also look for milky white residue under the cap, as that is another symptom of the ccv valve starting to fail. Check the rear coil springs, they commonly break near the bottom at the smallest "ring" so to speak. Again, a cold weather issue.
I agree with the 1st year model opinion. That's good to know about the front axle CV boot tearing, I never had an AWD car, so these are things I don't hear about. The regulators, however, I've had my share of issues with my last 01 325. If you don't mind, I'll copy and paste your comment and email it to my friend...he'll probably have his neighbor go w/ him, since he's a bimmerphile as well!
I have an e90 AWD no problems yet, it is still quite new. But I can offer that the car is excellent in snow!
Make sure to check all of the CV boots on the car. Also, please read the E46 WIKI http://www.bimmerfest.com/wiki/index.php?title=BMW_E46