I didn't have to decompile it to run light. I didn't change the map at all -- just ran with -scale 2. If you compare alpha4 to the older versions, it's considerably darker. This is because rad scales up the texture brightness (q2 textures were twice as dark as they should have been). The pb2 textures are nice and bright, though, so this in effect made it look like everything was unnaturally glowing. Once that was fixed with the new bsp pack, the reflective light was basically cut in half making everything way darker.
Anyway, I think it looks pretty good like this.