1st i would like to apologise is similar things are previously suggested. 2nd english is not my native language, sry 3rd all suggested numbers are just examples. Parts Factary - Building where can build your own custom parts, like tanks, engines, wings, structural parts e.t.c. Its place where can build dream parts for higher price and some work.... 2,5m 10m tall RCS tank?... here u go 1st level Max 15 custom parts 1,5m tank parts Structural parts, wings have 30% weight/drag penalties Engines have 30% Thrust/ISP penalties Limited size/weight High price (ex. 300% compared to similar stock part) 2nd level - 500k cash upgrade and 10 completed custom parts missions Max 40 custom parts 2,5m and MK2 tanks 15% penalties Increased size/weight limit. 250% price 3rd level - 2m cash for upgrade, 30 missions Unlimited parts No penalties and size/weight limits 200% price Choice of skins Custom parts mission - No cash rewards but high rep/science rewards. Examples Reach orbit using only custom engines Land on Mun having 5 custom parts e.t.c