Hard Mode (CAREER) Engine performance limter (part1)

Now that career mode is coming fast, a nice thing to add would be multiple difficulties.
Even if this game is made to be the more procedurable during rocket engines creation,, I think it would be interesting to add an Engine limiter in hard mode.

This limiter has (for now, i'll talk of it like it was already a thing) 3 different (and independant) principles:
1-Performance limiter: The sliders wich control engine's size, chamber pressure, nozzle throat size, nozzle size and gimbal range can be upgradable through time and after completing research via the science tree.
So, (for exemple) after unlocking "simple liquid rocketry" you can modify the size of the engine from 50% to 60%, it's chamber pressure is maybe not even unlocked, the nozzle throat size from 100% to 80% ( beacause it's harder to get good small throat than a big one) and engine bell size from 10% to 50%.
(Different fuels and cycles are unlockable too).

Part 2