My x3 was pretty trouble free up to about 160k miles when I traded it. It was a 6spd manual too.

It did have the cat issue. We assessed that it wasn't the cats even though the dealer said it was but no one ever figured it out and it ran fine so it wasn't messed with much. (now there is more info, mine was just prematurely high miled because of my driving.) I wish I had kept the thing now and it's hard to find another nice manual out there.