Essentially the BT-5 would be a slower M8 in AH. It offers nothing.
I could possibly see the Puma version with the 50mm. It would not be much more than the M8 in terms of armor, but it would certainly be a threat thanks to the gun. Not as fast as the M8 or M18, but not as easy to pick off with aircraft fire either. Hmm...
The Puma i've requested numerous times, a former squadmate of the 367th Dynamite gang "tull" would go ape crazy over it. Basically I look at it as a scout car able to "pose a threat" to late war tanks. Actually its armor is pretty thin other then machine gun fire, 20mm is enough to penetrate a puma.
Its armor was no better, but in terms of speed it did well over 50mph with a 50mm L/60 gun, although this sounds wonderful it carried very few rounds in general. It was a Recon Scout vehicle, nothing more, it was not ment to take on tanks, only if it had too it was able to defend itself and run away.
not as fast? It drove 53mph top speed - all vehicles in aces high are given by "Road speed" not cross country, the Puma certainly be a much lower eny vehicle (higher then Panzer 4 and lower then M8) but perks wise, I would guess 22? It has massive speed, and a decent gun with no armor, but nothing near and M-18, it couldn't tank any tank on head on - but it could easily flank and fire a kill shot regardless - where an M-18 has a chance to kill some tanks head on especially a Panther's front lower hull.