My X5 had the Michelin Latitude Diamaris on it when I purchased it. Odd tire wear from over inflation (REAR) and heavy cupping on the front edges from city driving. Loud on the road especially under light loads at cruising speeds. Feathered tires (just run your hand over the tire and you will feel the wear), will cause high noise. Once again nothing abnormal.

A replacement set is expensive but will solve the issue. Other tire options out there to consider also.

Alternative question, does the noise come in at 40 mph and get louder as the speed increases whether or not under load? See all Wheel bearing noises reported on the site.

I got away from the Diamaris tires because they were so noisy, wore out so quickly and cost/benefits didn't equate to a good value.

Parts don't have a definitive life span. What fails on one vehicle at 60,000 miles can still be going strong on another at 160,000. A bad expansion tank does not mean that the cooling system needs to be overhauled and neither does an air leak mean the entire air system needs to be replaced. At this point what's going on with the air and cooling systems are guesses. Considering the cost of new airbags or any other air system component or drawing the conclusion the cooling system needs to be rebuilt into the buy/no buy equation is misleading at best.

I would focus on trying to get service records or talking to past owner(s) and that PPI. rather than our speculation or personal experience.

What is the cost of a PPI in your area?

I will call the bmw dealer that the last owner serviced at and see if they willing to give out info to me.

The PPI cost in the South of $150 which is not bad. Found a reputable indy in my area with highly recommended review.

However we currently owning 3 cars and 2 drivers I will have to sell one of the Toyota once I get this BEAST as I dont want to sell my 03 X5. Decision, decision. Will let you guys know the outcome. Thank you for all of the suggestions and pointers.

More cars the better. One for each purpose in life.
Highway runner
Weekend burner
Daily driver
Costco Home Depot hauler
Then there are optional cars like:
Disposable - no deep investment, so no loss if wrecked, bent in parking lots, etc.
Rainy day (driver see above)
Toy/ garage queen. (Pocket depth determines make model)