1. Tirerack has tread depth specs on their site for all tires the sell (many tires ).
2. Tirerack also has a good article on how to measure tread and adjusting 2mm for wear marks to calc pct remaining.
AA Stage 2 - M3 control Arms FR - BMW PS2 - Dinan springs - APEX EC-7 - H&R front swaybar - GC street camber plates - Whiteline subframe inserts