Brake discs Bosch or OEM BMW

Rotors: Bosch

Use either BMWPartsDirect or GetBMWParts website, buy genuine BMW parts and find a good mechanic in your area (maybe even mobile mechanic who would come to you and replace rotors and pads). In LA I paid $180 for the labor to replace front rotors and pads on my X5, for example.

The brake disc was really cool

One of those checks will be a minimum thickness on discs and pads. Given you've only done just over 1000 miles in the vehicle since purchase, it would seem to me that the minimum thickness on the discs when the vehicle was sold to you was at or below that required as part of the pre-sale check.

Recently trying Bosch quiet cast though and have been pretty decent.

Another thumbs up here for Bosch Quiet Cast rotors & pads...they last longer in Buffalo's rust-belt conditions than any other brands I've tried, and they're quiet & they work great.

I’m seeing some very small cracks on the cross-drilled holes. At what point does this become concerning? These are the front rotors on a new G82 M4 comp after about 6 track days using Pagid R29 Yellow pads which I’ve used before with no issues. My preference is to keep the stock rotors rather than switching to non cross drilled rotors

am schimbat discuri si placute fata + senzor si sa ma atenuat din tremurat dar masina acuma trage usor intr-o parte si tot tremura putin volanul

Those BMW CSL drilled rotors suck. They came\nstock on my e85 M & they cause horrible pedal pulsation. I did a very deep dive on this after multiple sets & replacing multiple parts & checking everything 20x.\n\nThe bottom line is, those rotors are very susceptible to unlocking thickness variation or warped rotors secondary to water getting in the holes & corrosion forming around them.

If that's a factory BMW floating rotor keep a very close eye on that. Have seen more than one of those come apart (crack gets to edge, ring breaks away from hat), locks a wheel and full sends you in that direction towards the barriers.... Good buddy totaled his z4m and did like 6-7k of armco damage when that happened