I know your car was legal, you had it entered in the correct class for it's modification level unlike some others who just said their cars were M2 and got away with it. Unfortunately playing by the rules possibly cost you that engine.....who knows whether it would have lasted longer with another gear and no restrictor?
My comment was directed at CAMS tarmac rally rules for being too tight for the majority of performance car owners who's ordinary road cars already are outside the rules. Participation level would have to increase if they allowed some more realistic modifications. Maybe just for cars over 5 years if that keeps the manufacturers happy, perhaps?
The minimum car weights are too heavy (no one has realised it accounts for 2 spare wheels/tyres)
As for cars having to retain catalytic converters?????? yeah right