With as many high end features on this kit, Do you know why the WG control is handled by a simple spring rather than the actuator and a Gated Boost controller that can easily be adjusted from the cockpit?.... What are the benefits, besides simplicity, of the spring alone? (sincere question) .
The best is an electronicly controlled watergate. Mtntk knows this. However, that requires an additional control box. Cost, complexity, and added failure points. Mtntks goal was as high performance yet super simple for reliability.
Then you have a traditional wastegate canister. Works well for set boost level but not altitude compensating which was a mandatory design aspect.
Spring only is altitude compensating and 100% reliable. There is a slower boost response associated with it. But the EFR turbo more than makes up for it. It builds boost exceptionally fast. At least as fast as a cheaper turbo with a traditional wastegate. So in the end, spring only works well, easily adjustable, keeps cost down, altitude compensating, and 100% reliable.