depends. If your going with a complete mechbox replacement, you can get whole complete mechboxes. Most people recommend Systema complete gearboxes. Check out airsoftparts.ca for complete mechboxes
If you want to build your own for more control over your parts, build one yourself.
Installing a mechbox is pretty easy, check out mechbox.com for how-to videos, as well as how to assemble/dissassemble your ver.2 mechbox
And just a note, ROF means sacrificing FPS, thus range. And durablity is out of the question if you dont do a high ROF mechbox right, as the law of mechanics states, the more something moves, more likely its going to malfunction. Look for complete mechboxes that are called "high speed".
Originally Posted by White_knight
your right,when it rains the burger joint across the street does have cats for 4.99$ but that doesnt mean that i can just go get all the grape jelly i want