didnt need any spacers when i fitted mine.

You sure the 'spacer' they are on about isnt for the exhaust manifold?
basically with the standard mi16 exhaust manifold, it can hit the bulkhead of the car,
so you need a little 'wedge' shape spacer to go between the head and the exhaust manifold.

What driveshaft problems are you having??

if the car was a 1600 gti and you are trying to fit an mi16 or 1900 gearbox, then the splines are slightly different IIRC.