I think it was MT that got an auto 370 to run a 13.2 @ 108mph if memory serves so you are not far off stock if this can be repeated.
I remember seeing a PDK Carrera with only 385 hp absolutely destroy the v8 M3.
M3 V8 vs Carrera PDK [M3 is modded lol Porsche is bone stock]
Now the 370z has nothing like that PDK and is not rear engined with no driveshaft to add to parasitic power loss to the wheels and I know its not apples to apples comparing the 370z auto to the PDK but you wont need to be near the M3's power output to run with it as the Z is a good bit lighter and with those mods and tune you shoud be putting around 325-330rwhp. You would be very close to the M3 stock whp with a weight advantage. So it seems on paper you should have a chance at the very least to run with one. Lots of mag/bench racing we are doing though. Thats why you run em though cause paper numbers dont mean squat sometimes. Case in point the GTR lol.
BTW Ive seen tests of the M3 trapping as much as 113mph.