Hi Mikey,
in fact it was the 901-gearbox that you discribed.
Hi Turbo Haraune,
the 915 easily stands up to 300 PS and 350 Nm of torque. We are running it with Subaru Turbo engines with that power and it is perfect.
The 901 and 914 are also ok, but stand less power/torque. I have customers with 2.8 type 4 engines with up to 220 PS and torque near to 300 Nm with 914s, but they do not have a turbo and by this the torque at higher revs.
We offer conversion parts for both, 901/914-gearboxes and also 915-gearboxes. For 915s we have short nose cone (-20 mm), traverses and axle flanges. Have a look at our site
www.bugat5speed.de and look for Umbauteile Porsche-Getriebe (for 901/914-conversions) and look for Projekte for 915-parts