A fair bit of my info is personal testing but lots is also comparing info on the net, alot from Trev. I only have a EME pipe and a ks 1060 pipe.
The re2 and es pipe I dont own but have gathered alot of info that to me suggests they handle a 60cc motor better than a ks 1060, at least for peak rpm. Bear in mind peak rpm is not neccesary everything, well thats my opinion. Perhaps when running a larger prop, say 25 10 and thus lower peak rpm and longer header the ks 1060 will be fine?, food for thought.
If I was setting up a mvvs 58 and had my choice of pipe I would like to run a es pipe due to weight. But I would have two concerns and so not peak it header wise for two reasons, first the transition could be quite brutal, second the es pipe could fail under the exessive heat.
This is only theory though, im happy with my ef extra's power on 58 gx on ks 1060.
I wish I had as much time and money as you canadian boys to experiment some more
.