Yes, the MX400 rings are the exact same rings as the Esky rings. Part Eflite # EFLH1158 (even bagged the same as the old Esky "0" rings) and it lists for about 2$ for 4 "0" rings. My LHS interchanges a lot of parts between the two Helis and that happens to be one of them.
The Mike Trueblood dampeners (2 kinds) have been posted as not working well in the past as cutting that materal is very difficult to impossible to get it exactly in half and perfectly straight and that's what it takes to get the same tension behind both blade grips so they are exactly the same and that is very important. If the dampeners are cut even a hair off it is like dealing with a slightly bent feathering shaft or a weak or damaged dampener (which were trying to replace to start with) and you could have tracking problems that come and go at diff speeds and loads on the blades. Still have the problem with them not cinching down on the Esky feathering shaft properly due to differance in the way they are tensioned. Been there already with those dampeners, money wasted when I could get the stock ones for less, there is also a post on the problems someone encountered when attempting to cut and use them a long time ago. Same with using hard teflon washers instead of the stock "0" rings and also the Traxxas 2362 shock rebuild kit dampers which turned out to be much too soft, tried that one it was almost worth a picture when the blades started slowly sagging in slow motion as you watched... and when you ran it up the disc looked as if it had a funnel shape from the side as they were about 1 1/2inch higher at the tips at half stick (also damaged the bearings in the cnc blade holders and the cnc blade holders themselves from that little experiment).[]