So I found some info on our transmission 8HP51 vs the F30's transmission 8HP50. These are the spec comparison gear ratio stats between the two. They're in Japanese because they're numbers for the A90 Supra.
Also our transmission is greatly underrated, there are members on the A90 Supra forum making over 500-600whp & 400+ lb ft of torque, and the transmission is still handling it.
We on the 330i platform with B48 should not even begin to worry about tranny reliability, unless you are making some serious power
Check attached: