RE: Q 500 getting started
There was a rumor that Lone Star Balsa was running a batch of Skat Kat kits, but I'm not sure if it ever materialized.
Not a lot of actual kits out there.
Should be able to find the Lanier Dominator which flies very good, Bill Vargas is still selling his Racer 2, but that may be it.
Vipers and Predators are just fine for 424 racing.