I have a solid front mount in mine and its fine, but we put a solid front mount in my mates car and it caused a bit too much vibration for his liking and so we swapped it back. the funny thing is our cars were almost identical in spec, both were MK2 with abf, both used bonded rubber febi rear + box mounts and the same make solid front. only real difference was he has coilovers and i have good shocks + springs.
the reason we went for solid front mounts is we had 4 branch manifolds, its a good idea to fit them in this case to reduce the chances of the manifold cracking. I dont actually have a 4 branch anymore so will probably swap back to an oem type mount in the near future