Nice car Stu but I wouldn't say no problems.....

Has it had a new bottom end at any point? Nicasil problem - well known - BMW should be able to tell you if it's been done in the dealer network under recall if you give them the chassis number.
Ask them at same time if it's had the steering column recall/.
Has it had a new water pump at any point? - you might have a plastic impellor one and if it goes and you don't catch it quick it might take your head gasket too. The temp gauge needle shouldn't waver when up to temp - should stay rock solid - if it even starts to inch up to hot - stop quick and get it checked.

Worn RTA bushes can give funny handling - rear damper top mounts can "clunk" over bumps - the E46 M3 Convertible ones are better as a replacement.
Bushes at rear of front wishbones can give vague steering and similar effect to warped discs
Check rear brake pipes as well.

Hope she enjoys the car though