Raj Don't know the ratio but I know the M5 has 3 turns lock to lock and a turning circle of 11.2m, you could compare this to your owner's manual. It's probably the same box. Does any one by chance happen to know the stock steering box ratio of the e28 m5? I'm trying to figure out if an M5 steering box would be a worthwhile upgrade for a non-///M e28. TIA.