Does any body know the full differences between these two blocks?

We have a 205 engined rally car at college but it is 4 wheel drive.

I thought the 205 was designed for 2 wheel drive and the 200 had extra webbing to accomodate a front diff.

Can any body please confirm this? Also how long would a 205 block last with a 4 wheel drive system? Please bear in mind the car is Group A spec and will be a tarmac rally car.

Thanks in advance.