Alright, it looks like Advance Auto has two different Pro King brand kits available for my S20 transmission: BK326 ($182, no syncros) and BK326WS ($272 with syncros). I have a neighbor with access to a hydraulic press (through a friend that works at a machine shop), so I've decided to opt for the syncro kit and go for broke (without, hopefully, actually breaking anything). Wish me luck!