Really happy with the performance gain of modding the ZMR into a slim build. The center of gravity improvement from the lower battery is a very noticeable improvement in handling. Here is the spacer, I made some small mods to it myself. The final blue spacer was printed in nylon 910 which was passed through a sharpie prior to printing to color it blue. http://www.thingiverse.com/thing:1255122
I also cut down the top plate to just cover the front two rows of spacers. I used a jigsaw. The carbon fiber cut like butter. Just be sure to wear a gas mask while cutting carbon fiber.
If I could do this again, I would buy the new red bottom EMAX motors, they have insane thrust. I would also get the seriously pro acro FC. $25 for an f3 board is very reasonable.