-Gen-X Global 4+1 Harness [Black]
-Empire bottle cover [Black]
-It lowered the pressure by 15+ psi
-It made my gun sound one heck of a lot quieter than it already was
-Reduced the kick by a noticeable amount
-None as far as I can see
People complain about the colour wearing off, but it hasn't happened to me yet (I am, however, sure it will eventually). Personally I assumed that would be a good thing because it shaves some weight form it. It's not like you see it in there anyways. It reduced kick, made my Ion cycle faster and a lot quieter. Reducing the pressure means a lot more efficient too. For $40 you can have it pay for itself and more over time in the gas you will be saving. I play more woodsball than I do speedball, and this bolt makes my gun so quiet. I have had several people comment on it and say how they can't really tell where I am by trying to hear me.
Overall I would say if you are going to mod your Ion, this should be top priority. It will help performance, and it will, over time, pay for itself. I have yet to have a problem with it, and I only see good things from it.