Do you have camber plates? BMWs need a LOT of front camber - at least 2.5 degrees in the front, but most guys run over 3 degrees.
Edit: Just checked - you don't.
You're build is awesome, but you're just missing the small things to really help you out. I would strongly suggest you consider having them pull the alignment pins and pulling the camber out as far as you can go (if you don't want to buy camber plates) but changing tires won't help you. You're running on the sidewalls of the tire.
Second edit:
https://f87.bimmerpost.com/forums/sh...1&postcount=13
@Zm2 may be able to guide you more - I have a lowly M235i, so my suspension geometry is slightly different.