I know this is an old post, but i wanted to comment as i recently acquired a Rep 2X with the IDE upgrade on it... WOW... Just plain WOW...
The bottleworks setup was nice, i worked on a few that had them on there, but this complete Z-Axis replacement from IDE is simply put amazing. I leveled it and printed for hours, multiple prints and heating and cooling cycles and then checked it again, it didn't move at all. I have their full Z-Axis replacement and their HBP replacement as well. The HBP is really top quality. I have two of their glass plates that pop on and off with magnets on the HBP, what a great system, finish a print pull the plate pop in the other plate and hit print again while the first one cools. Talk about turn around time!
They are a bit spendy, i would love to have their Z-Axis upgrade in my Rep 1's, but i have three Rep 1's and it would cost a small fortune to upgrade them all, $250 each for the Z-Axis assembly and $150 for the HBP. But if i have any HBP problems i will probably at least do that upgrade to my existing Z-Axis, i have the aluminum wrap around supports on my stock plastic arms for now and they work great.