Having seen and shot it I'm very impressed by the build. Very solid/consistent performance. The hopup application is just deadly.
I'm looking around for a backup/extra PTW and might go this route. I did not like the buzz (not so much as a noise as it was a feel in the hand) with the motor. It might smooth in a bit but it was very pronounced.
I can't help but shake the feeling that 2 out of 3 of your batteries are underpowered for the system. I've seen on their facebook page how they recommend a 11.1/15C. Your batteries are putting out 16.1-26A in the best conditions. I know the PTW electronics need 30A per shot, every shot...or you risk failure. Even if they've optimized the electronics/motor I can't see it being below 20A...but who knows.
From the close ups of their hopup mod...I still prefer my own mod

It does look a whole lot better than the stock hopup though.
I wouldn't go with all the bells and whistles but rather a plain build.
All that said and done I'd be hard pressed though to just get a 2012 SCK and a full set of boards and motors from FCC...then mod the rest myself.