finally hector's saying some decent stuff
Ok, so those are good prices on good parts.
Make sure the feedneck is compatible with your gun (Ion XE threads, right?)
The bolt will make a GREAT difference. Make sure to drop your pressure greatly and back out the velocity governer on those quite a bit once you install the bolt as the velocity of the paint will go up a LOT.
Make sure the stuff you're getting is in actually good condition, so ask for plenty of pics from every angle.
Furthermore, a barrel may be a solid idea if you're running the stock (and fat bore) barrel.
Where are you generally situated? (like the state/country/and/or city?)
If on a budget, try out a Lurker Eigenbarrel.
They're the best for the price. Feel free to challenge me on that.
Depending on where you live, though, you should check out the .684 or the .678 back.