I'm having a hard time finding much info on Traxxas' BEC unit. What I think I know so far is that it puts out 6.0 volts to the servo. I can't seem to find out what the amp rating is and if the voltage is adjustable. If anyone knows more about this I'd be very appreciative.

no info on this part # 2260..https://traxxas.com/products/parts/2260?t=overview

It only puts out 3a. If you are able to, I would suggest a Castle Creations BEC as it is 10a and half the price.

The plug and play simplicity was enticing, but 3 amps is all but pointless. I suppose it might help with the stock servo but I'll be swapping that out sooner than later, plus I have several other rigs that I need one for and that won't cut it. Castle it is. Gratitude for the info.

If you want plug and play, heyok makes a nice plug and play bec that you can adjust the voltage output without an expensive castle link. You can order one with whatever battery plug you need.
on a side note, a 3 amp bec generally is enough amps. Even if your esc puts out close to that, you'll be taking the stress and heat off of you your esc. And the jst connectors are only rated at 5 amps, so don't expect 10 amps on a single servo line.(that's why larger becs have 2 outputs).