I recently used systema shims and systema ball bearing bushings and did a re-grease. noticed a large improvement in sound and firability. The stock nylon bushings need to be replaced for sure, its only a matter of time before they wear out with an unshimmed gearbox. Other than than save your money and use it on bb's and have fun with the hk 416 theres no sense changing everything at the get go, just upgrade as things wear or break.
Bolt Action Level 2 Certified