PDI V2 Hop-Up Chamber - Few Questions

I was thinking of purchasing the PDI V2 Hop Up, I just had a few questions that I was hoping someone could clear up. The V2 Hop Up is only $72 and the normal PDI Hop Up jumps to $130 just because it comes with the cylinder head or am I missing something? So if I get the V2 I need an AEG cut barrel, PDIs are pretty high priced and I'm unable to find any other 430mm cuts. Does anyone else have some recommendations? And last but not least the bucking, I have a FireFly hard bucking would I be able to use this in the chamber?

Thanks,
Ping

Link to Hop-Up