The empi shafts are made for a trooper which use a smaller inner CV (green cup) and that's why you noticed slop. I was only using empi because I replaced my passenger side cup with one from a trooper to make it easier to source replacements. I've had some recent bad luck with the empi shafts but it was during off road trips. I doubt anyone would break a shaft street driving but they're still junk imo.

Also, the race/bearings from the empi won't fit on an OEM shaft (or vice versa)