Schwalbe Marathon Racer 20x1.50 (40-406) HS429 Tire - The most popular recumbent trike tire by far. There is a reason that this tire is the default stock option on so many recumbent trikes. Every tire is a compromise of weight, speed, puncture resistance, and longevity and the Schwalbe Marathon Racer is the best option for the average trike rider.
RockShox Monarch RL Rear Shock 6.50x1.50 (165x38mm) C2 - Rockshox Monarch RL rear shock. Featuring silky smooth travel in a new lightweight design, Monarch floats through bumps even better than before, turning rugged trails into tire-gripping velvet. The chassis is lean while maintaining the durability and adjustability needed to bite off huge chunks of burly trail action and epic cross country.
Schlumpf 27T/68 High Speed Drive w/155mm Cranks - The Schlumpf High Speed Drive is our favorite piece of cycling engineering. This planetary gear setup will give you higher high gears and lower low gears. If you have a trike with a 20in rear wheel the HSD will give you back the high end you are missing.
Ventisit Seat Pad 38x23/15 cm Comfort (3cm thick) - An incredibly breathable and comfortable seat pad for your trike. The open weave mesh offers incredible ventilation that will keep you cool on outings. The mesh features a no-slip grip that will keep the pad on the seat as you ride.