I have an bolt-in Autopower harness bar for an e90 M3. I test fitted it but never actually installed it.
All the hardware is included.
Item on Autopower website (Item Race Roll Bar 60907):
http://www.autopowerindustries.com/r...013?syear=2009
Pics are here:
https://photos.app.goo.gl/SBqaW84Uh8HsGhXK8
Retail: $750 + shipping (about $250)
Asking: $650 shipped within 48 states