I've so far bought two of these kits, and I only have a few complaints.
The first being that the wires come with a far too short to actually use, the second is that I've had a lot of problems with the darts just fluttering through the air because the canted flywheels can put too much of a spin on them. The orange barrel seems to help but they still occasionally flutter which is really bad if you are trying to hit anything from range.
But, other than that it's a great kit!
NOTE: I have one of these in my hyperfire and it loves to rip the heads off of the darts!
I purchased this as one of the first to modify since it came with everything. The cage and wheels are beautiful. Running on 3S, it took the Hyperfire from mid 60 FPS on alkaline batteries to average of 120 FPS and the fire rate is incredibly high. Have been using it for 2 months and the only issue I ran into was a burned trigger switch (the included ones are 5A micro minis) and then later I had to threadlock the motor mount screws which I think is even more required on an all metal cage. The metal barrel insert is fabulous. The diamond serrated pattern on the flywheels have excellent grip but will induce some very minor dart wear over a lot of use. I highly recommend this package and if I was doing another Hyperfire, I would get it again.