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
"I call suffering my brother. I love him like my mother. We look out for each other, we'd die for one another.
I fight, I brawl, I feind for this. I scrape, I crawl, I bleed for this.."