as a generalization all-motor is unreliable because in order to achieve high horsepower you would need agressive cams that function well during high rpm operation, also increasing the compression ratio is necessary which changes the dynamics of that engine...
as far as the C5 all motor, i think this is the best and only way for this engine. why? because it was tuned to be an all motor car from the factory, it already has a high compression ratio and is meant to be revved freely in high rpms, whoever disagrees need to be shot
