The total length is 56mm, but the distance between the middle of the mountpoints is 48mm on the Xray shock, not 50mm like on those.

I have similar sized shocks, I fitted them to my car and at the front it was ok, but the rear didn't quite hit the bottom. This should be able to be fixed by shaving the bottom of the lower ball connector (The plastic part) as the car does bottom out if the spring retainer is removed. so you just need to make a few changes.

Sorry I cant help any more, hopefully I will get more feedback on them from the people that asked me to make them. So I would hold off buying the 20mm super low ones for a day or two.

Thanks