I know a good visual clue to bad mounts can be seen on non m engine mounts as they will create a hole in the hood insulation right above the power-steering reservoir cap. I changed mine out in the blown 330ci at 120k
On my current m3, @ 40k miles, last time I chcked it looked good will be looking for one at around 60k with new spark, and general maintenance
"We've come a long long way together, through the hard times and the good. I have to celebrate you baby, I have to praise you like I should...
I have to praise you like I should.."