I've always used NGK plugs. The recommended ones for the 8v engine have 4 electrodes so they are the same as the bosch super 4s, but much cheaper.
For oil got direct to VW, their stuff is only about £15 for 5l.Oil filter, get VW one too, they have non return valves to stop oil draining from the head.
The 8v responds well to intake modifications, so a new panel filter or even better, a pipercross/K&N will give a nice increase, as well as putting a cold air intake and/or derestricting the airbox.
For suspension, you can buy some eibach springs and new boge shocks from GSF, should renew the touch of the car. Remember to put new top mounts all over.
Polybushes give a very nice feel, it completely changed the driving characteristics of mine, turn in was so much better. Polybushes are reasonably cheap too.