The upgrade to the new Starter System is not just a motor swap. The new system replaces the inlet cover, motor housing, housing supports, bendix assembly, and spinner nut. I believe the engine has to be disassembled and the compressor modified for the new spinner nut. I know it does on the larger engines but not absolutely sure about the 500. So it's a pretty involved swap.

The new starter is a very high quality unit. It's an all CNC machined, metal assembly with an easily removed electric motor. This makes the o-ring very easy to replace, if necessary. However, my 500 with this system has had over 200 starts on the original o-ring.