Seems like Royal Purple is the best choice in synthetics these days from what I've searched. Which one should I use for a '93 T5 w/about 80k mi. on it? Royal Purple Max ATF or Royal Purple Synchromax?
Max ATF -- Recommended for all applications where Ford MERCON® / GM DEXRON® III transmissions fluids are specified. Provides outstanding rust and corrosion protection.
Synchromax -- Recommended for manual transmissions that specify automatic transmission fluid, multi-viscosity motor oil or straight grade motor oil.
IOW, I don't think it's going to matter. If it were me, I'd go with the Max ATF.