For those of you saying 100k center diff is like a slipper....no it is not unless you maybe own a xray, lol. I had a few guys that are xray and b44.2 owners with slippers in the center. They wanted to see how a center diff felt. Mostly because of the xray 2015 and b44.3. They wanted to see if the investment was worth it. The could not believe how much better the F/R power distribution was with the center diff and 100k. They said the same thing I do. The center diff, even with 100k oils is much easier to drive and put power down with. And on out medium but track, my front wheels still balloon going down the straight. For that track, I have been debating 150-200k. For my high bite track, I prefer the 100k. I tried the 50k and 75k options and didnt like it. The car was too twitchy IMO. But to each their own. Diff oil is cheap and pretty easy to experiment with. I highly suggest you leave clearance on the center diff to "twist it out. Thus lowering the amount of screws you need to remove to get the diff out from 18 to 8. I run my esc behind the motor and I like the balance better. I really need to find someone with the SkyRC scales and see what my corners are at, but when it comes right down to it...I like the way it drives better with the ESC back.