The Smooth Stepper is available from a variety of sites. It's made by Warp9. The 203's are a bit more advanced than the 201's in that they have lots of failsafes. The "V" is for "Vampire" meaning "unkillable". That's what got me to get those drives. However, the b/c drive I'm using can't use standby current let off. It needs full current even in standby, so that's why I had to use 201's. The power supply is a 975W, 15A system, really way too much for what I need;)
I don't mind sharing, none of this stuff is proprietary, just takes research. There are a lot of good websites out there for CNC parts. For general electronics parts, I'd walk your local electronic stores. Act the complete idiot and get help and advice on everything. I spent hours at my store, and I'm sure they thought I was a moron, but I don't mind the hand holding when out of my element;)
Barry