Mine had 77k when I bought it, full BMW history with warranty. I thought I'd be ok but the head gasket needed replacing 2 weeks ago at 84k miles and the boot floor crack is going to be repaired by Elms soonish...
I'd say check boot floor, head gasket, first service, service book with the invoices, number of owners, software updates for SMG.
Mileage is not an issue, a careful owner who has loved it for more than 3 years speaks volumes.
I love my CSL and will keep her in top condition and I will be doing 16-18k miles in her every year. Mileage has never been an issue to me... E46 330i 166k miles, Porsche 944 Turbo 216k miles, E34 M5 165k miles... all strong engines and looked after.
Sometimes a high mileage car that is used regularly is better than a low mileage one that is hardly used... but I'm biased!
