Wife claims her car is faster (340i). I think my m235i is faster. We finally lined them up today.
Both cars automatic. 340i x-drive is stock. My m235i has wagner catted downpipe and vf hex stage 2 flash tune. The intake and exhaust is otherwise stock on my car. My car is RWD. We tried this in winter and I couldn't get traction and I lost badly but in the heat my car grips and goes quite well. You can really see the torque difference early on from the tune.
I do have a piggyback tune for her car that I need to put on. That will likely even out or even turn the tables.