The Moab shock from Cogent Dynamics will change how you feel about your KLR. You may like it now, maybe even like it a lot, but you will absolutely fall in love with it once you mount up a Maob shock.
Spring duties are handled by a custom spring available in either Standard or Heavy-Duty weights. The Standard spring will be fine if you are under 250 pounds and don't ride with luggage or passengers often. Ride heavily loaded or with a passenger regularly and you will probably want the Heavy-Duty spring.
For a true comfort and performance package, we highly recommend upgrading your front suspension at the same time.
If you have '87-'07 KLR, you MUST order a new mounting bolt. Not required for 2008-2018 models.