Tarmac Rally Stratos Build begins

[Strat Fan]

Isn't there a similar problem with Integrale boxes on uprated cars? I have a vague memory of casings being machined around bearing houses to accept a sandwiched steel plate to strengthen them.

I can't comment on the Integrale but there is the 3mm steel strengthening plate which can be added to Fiat/Alfa boxes between the bell housing and the gearbox casing which is used to help prevent the diff/crown wheel from separating from the pinion shaft. This requires 3mm to be machined from the gearbox casing to me it fit.
Neil did this to his old 164 box. That bit didn't fail but he stripped 4th gear shortly after....