I wouldn't agree with the high-mileage vs low mileage car thing.
As long as the car has not been sitting for 3 years in storage, giving it a good drive every month is far better than the BMW that has been driven every day... rain, snow, salt and wonderful Toronto roads.
Low mileage is the way to go, because as you hit higher mileage, there are way too many things that wear out on these cars.
This is a good list.....
1. - Check the wiper motors on e46 - crazy expensive to fix - part alone is $300-400
1. when the cooling system was refreshed (accs belts, fans, rad, coolant flush)
2. is it still the original clutch and if so how much milage does it have
3. What condition are the shifter bushings in (if your going for a manual)
4. Turn the aux fan to low - and check if it squirlly
5. roll down the windows and check if the exhaust heat shield is cracked
6. Window motors
7. Open the trunk and check for bubbling under the rubber
8. When was the suspension done, ball joints, control arms, bushings, springs, shocks/ struts in that order
Adding Some more.
9. Rust. Despite what people say, BMW's rust. Original paint, winter driven
E46 BMW's rust. Under the hood, bottom of the doors, rear fenders. I'm starting to see a lot of E46's rusting like 20 year old Civics.
I was even told by BMW Service Manager, where to specifically oil/rust proof the E46... because they will rust otherwise.
10. Window Regulators. Move the windows up and down many many many times. You should not hear any noises, and it should be smooth.
11. Door Lock Actuators.... open and close the locks with the key and the central locks. Door
12. Central Locking Module... BMW has as a very bad problem of these failing. Random door lock/unlocking issues will result. Combine this with your failing Door Actuator, and you're screwed.
13. Ball Joints/Control Arm specifically, & Front end - this is all part of the safety, but pretty weak. Higher mileage.. 200K or so... they may starting going again. A lot of people change them when the car is newer....
You'll only know this if you own the car from new. You'll see they wear out early.... I've had a few new ones...
14. Steering Rack Leaks - check for fluid drops...
15. Stay away from automatic E46's..... They have horrible auto's....
Think Chrysler Mini-van
16. Stay away from the early E46's... the rear subframes rip out... Coupes...
17. Vanos (BMW's VTec version of their head - I'd take a Vtec or i-Vtec over double vanos... they don't fail like BMW's does). It starts degrading as you drive.. .pretty bad design.... check out "DrVanos.com" and you'll see. If the motor is noisy, it could be the Vanos unit.
18. If the BMW has a check engine line, walk way.