i upgraded the rear shock on my AT with Ktech spring for a 250 lb rider and it was well worth it. i have Hyperpro progressive spring in the front end and so far, I am not loving them. I did not install Hyperpro progressive spring in the rear because the shock linkage already has a progressive increase in spring force simply due to the geometry. I have used Hyperpro suspension on other bikes with great results but for our Africa Twins, I think straight rate springs from companies like Ktech and RaceTech are better.
For the front end on my AT, I decided to spend some serious coin and buy the TracTive X-TREME Fork Cartridge Kit (-20mm low). I have not installed them yet. I decided to get the lowering option because I will not be riding off road in challenging conditions. I also bought a lowering link for the rear. It is better to use a lowering link as opposed to buying a shorter shock and I like the Ktech rear spring anyway. Tractive makes some of the best suspension components available and it is not necessary to spend that much to get a significant improvement. I know the folks at Cogent Dynamics recommend trying straight rate spring upgrades in the forks for a lot of their customers. They told me the valving in the 2020-on Africa Twins is decent enough for many folks to be happy with just a spring upgrade.
Ohlins also makes a front fork cartridge upgrade kit and Cogent sells it but I think the Tractive cartridges are a bit better. Some links if you want to learn more about two of the better vendors and their offerings:
Cogent Dynamics designs & builds custom motorcycle suspension upgrade solutions: Shocks, Springs, Dampers & more. Located in the mountains of Asheville, NC.
www.motocd.com
Check out the deal on TracTive X-TREME Fork Cartridge Kit (-20mm low) / Africa Twin '20-On at Ted Porter's BeemerShop
www.beemershop.com