[Crazy Jetty]

Give it time on the vehicons. Patience will be your friend. Because while still underproduced, it's slated to be in a fair few more waves. So it will eventually become much more easy to find. There's a big panic now to get it, but it *just* came out. Soundwave's now getting pretty easy to find, and Vehicon will too.

As for FE Prime, everything I've heard from all my friends who've gotten both the mainrun and first editions... FE Prime comes up extremely lacking to his mainline voyager counterpart. Bulkhead too.
The only reason the FEs are held in such high reguard is they're so hard to get, and this fandom tends to almost deify things they don't have.
The first editions are not more screen accurate, and most of them are extremely clunky first passes. (There's a reason Hasbro cancelled them to make newer, better molds after all)
So I'd suggest going for the regular version (BBTS has it on sale for $15, even), and avoiding placing yourself for disappointment.