I took a chance and bought some Koxx K1 160mm cranks from Renegade Juggling. In the past it seems, from reading other posters, that Koxx was not making ISIS standard equipment. However, the cranks I received are definitely ISIS standard as they fit perfectly on my KH Ti hub 
As to weight and quality, they seem to be well made, having a pedal insert like KH, black anodized with the K1 polished aluminum, maybe a tad lighter than KH Moments. I do wish they made them in other colors, but black and silver looks nice, so I wonāt complain.
So now we have another crank choice and finally a true ISIS crank in 160mm!
ISIS Tolerance
It is a well known fact the the Koxx cranks will fit on KH hubs. But lets see you put a pair of Moment on a Koxx hub. Kox makes thier ISIS on the upper tolerance. Once you buy a Koxx unicycle you are also stuck with their cranks!
Unicorn
Koxx and kh always āfitā each other, or that is what Iāve heard, Iāve heard of cases going both ways. The difference is so small that it will not stop you from putting them on, but they will wear faster and the splines will slowly get smashed to crap and the cranks will be worthless. That is the idea anyway.
Iāve never tried it, thinking about it, for the price Iāll probably just stick to moments, qu-ax and onza.
Report back after some real use.
Well, they sure do look tight, and consistently so, but I will ride them and see how it goes. Iāve done a fair amount of working with metal and I donāt see a tolerance issue, otherwise Iād send them back and get a refund on my $95 investment.
Maybe things have changed with Koxx? I just wanted a 160mm crank, donāt care who makes it. Iād certainly rather ride auni specific crank than take a chance on a BMX crank, esp for twice the price!
Iāve heard they were fixing their hubs/cranks to proper isis a while ago, but never heard word for a long while.
Maybe they finally did it?
Tolerances cant be that tight if they powdercoat hubs and cranksā¦
This is confusing me, Iām not sure what your talking about getting at. Please explain.
They donāt powdercoat the splines of the hub or cranksā¦ not on kh hubs and the cranks Iāve used.
Besides, I think the difference of pcāing is far less that what the koxx/kh used to be. Iāve never done it personally, but I think if there was no problem there wouldnāt be such a fuss about it and even be on distributors websites.
No wiggle so far, went on tight and smooth, did have some pedal loosening so I had to crank them down on the pedal washers, which caused one to self destruct 
The additional 10mm crank length, over the 150 Moments that I have been riding, is really helpful with climbing and descending but without a significant difference in spin rate or āfeelā. Iām thinking of putting 160ās on my sonās muni to help him with powering up big hills and over rought terrain.
I pulled the cranks last night, the splines look great! Iām convinced that the K1 cranks are truly ISIS compatible now.
BTW, if you are putting K1 cranks on your ISIS KH or Nimbus Hub, the spacer between the bearing and crank should be 6mm. An 8mm does not allow enough spline contact; 8mm is what Moments use.