John has this commercial test roller from Slot Car Corner.  This is a testing tool that allows him to Tune a car without much actual track-time (and he seems to be doing very well with that!)  It needs a variable DC power supply and you have to use gators to splice a controller in line with the Red/+ post if you want to test with a controller.  Uses: break in motor and drive train; test Roundness and balance of rear tires; test rear wheel RPM (requires a laser tach (like many of us have) and some strips of Reflective tape on the rollers).  This is mainly a high quality roller mounted to a convenient base with some pick-up rails and posts.  It also has a convenient built-in LED voltmeter, and an adjustable “stop” for cars with different wheel-bases.  It sells for $120-ish.

JK Products sells a similar 1-24 oriented test/break-in “block” but it has No Rollers  (yet only $60).  1-32s will fit on it; rear tires fly 2mm off the track height.

For many years TAMIYA sold a 1-32 scale “Mini-4WD Speed Checker” for $45.  (what HSARC uses). It has a LED display showing speed in KM/hr.  It does not have power rails or terminals (banana posts); many Slotter’s add them, and remove the front rollers – to make a “Dyno”.  Rear wheel RPM testing requires a laser tach & Reflective tape on rollers.  It has a Non-adjustable “stop”.  They are out-of-print and rare (can go for +$150); I recently bought a NOS in the box from a Russian dude for appx $50usd and $12 shipping (for use with my Mini-4WD and slot cars).