You can run the versa planetary without modifying the CIM output shaft. I talked with Aren at vexpro, and the original intent for the CIM adapter was to leave the shaft unmodified. I do not remember the reason for them suggesting the modified shaft for normal usage, but we ran mostly unmodified CIM shafts with the adapters as shown below.
You have to leave all the stages in the gearbox for shaft clearance. We did have to shave off the end of the output shaft around .010"-.020" with a file to remove a minor interference.
We had zero issues with the setup for the 2015 season.
