Jim - Have M2 shocks on my 2014 RTL. Happy with the M2 product. Still adjusting the suspension to get to where I want it.
There are a good number of aftermarket shock manufacturers out there that can provide you with shock(s) to meet your requirement(s) of a "plug and play - forget and go ride" scenario. If you want to "play" and tweak/tune the suspension to maximize your riding pleasure and performance, you can do this as well.
Elka shocks get a bad rap on this forum; however, a company in Ontario, Accelerated Technologies, uses Elka shocks on snowmobile and ATV suspension upgrades, exclusively I think. The Spyder and snowmobile suspension systems have a lot in common. If the Elka shocks did not perform, this company would not use them, and snowmobilers would definitely let you know about it. I surmise that there are far more snowmobile and ATV suspension upgrades done than Spyder suspension upgrades.
Shocks do not need to be rebuilt on a specific maintenance schedule. If you were off roading and ditch banging in a Dakar rally, maybe yes. Theses Spyders do not take the pounding a snowmobile or even an ATV does. People don't change their car shocks until the car goes down the road like a kangaroo, hopping all over, and sometimes not even then.
I believe the reason the recreation vehicle market is more interested in changing/upgrading suspension and such is because these are our "toys" and we spend time and resources on making these ours, and in doing so, we tend to imagine all sorts of issues.
If the shock does not work, rebuild/replace it.
This is an interesting thread for reading. The fellow decided to do a rear suspension upgrade using the OEM supplied rear shock:
https://www.spyderlovers.com/forums...ng-it-Adjustable&highlight=suspension+upgrade
All sorts of possibilities.
Enjoy your Spyder.