The 86SB suffers in one thing only to me, flimsy frail tonearms which aren't rigid. With a good working mech, new belt and hopefully motor gromets which haven't collapsed (and rotors that haven't come unstuck), the decks can perform very well with minimal drive noise. Mine tends to motor-drone through the speakers a bit and I put it down to grommet fatigue, as supporting said motor by hand underneath a little, this drone all but disappears.
Once the trip pawls on the cam are judged free with no stiction, the arm will take modern cartridges such as the AT range (up to 530 I feel) and also the soon to retire Shure 97XE, which likes the higher capacitance cables these Garrards usually came with. Even the venerable antique M75-ED can still be got I saw recently and these Garrard arms were low enough mass (just) to be able to take them. I'd avoid the more durable medium compliance cartridges as they'd upset tonearm resonances too much (Sumiko Pearl, Nagaokas and suchlike). Mine sounds great with a vintage ADC XLM III and descended Phase IV fitted, tracking at 1.3g or so. Oh, and a replacement O ring on the groove under the geared part on the platter hub quietens the mech down superbly, making it almost silent in operation (I think it's 15mm x 1.6mm but can't remember exactly now - they're cheap enough and too tight a fit will shorten the life of the ring).
The fancy mats on the mk2 models weren't good for record support in my opinion, but if the plainer early mats can't be got as spares, a 3mm cork mat works well (I think you can get darker less 'cork' looking ones now as well.
Good luck. I find these decks hugely enjoyable to work on and listen to as one's expectations are so low and then they surprise by being far better sounding than their flimsy arms would indicate.