I should be getting my car back from the shop either tomorrow or Tuesday with the full drivetrain swap and a 2.81 gear. I'm already running the stock M3 tire size (275/35-19). I've reset nothing at this point but will once I have the car back. I guess I'll find out if this is outside the "comfort" zone or not for the M3 software.
It chirps into 4th and I find that I want to hold longer before shifting now. Maybe I'm going back to E36 muscle memory with the lower gearing.
Going to get some logs soon.
Oh and tire size won't matter. I had in my mind speed equivalent not shaft rotation and it was explained and pointed out earlier to me in this thread.