Going to be interesting to see how you gearbox gets on
I haven't heard of many gearbox failures on these cars and I did change the gearbox oil last week. There are people on MPSOC running significantly more power (some over 400bhp) without any gearbox issues.
My biggest concern would be the rear diff as the standard mounts aren't the best. I won't be doing launches or going beyond much beyond 300bhp though so it should be fine.