I’m planning on taking the M on a Euro trip next year if I can afford it, but if your thinking of doing one I would defo recommend taking the 2.8 it’s so easy and more relaxing and so much fun in the mountains. I’ll take the M once but I know it’s going to be more work,the cluch,throttle and brakes suspension all make it tiring to drive for long days which we handle ok in the 2.8 which is fairly standard
Sounds like the brakes, clutch and suspension need a refresh. happy to help

