It's not practical for an efi system to be installed on a 25 year old two stroke engine. The injection systems that are used on two strokes engines today require TBap sensor, exhaust temp sensor, crank position sensor, engine temp sensor and and a control unit with a very intraget fuel/ignition mapping. That requires a stator that can supply sufficient power. Not to mention the only big gains would come from a direct injection that requires injectors to be installed directly in the transfer ports. Cylinder disgn and port setup changes dramatically with a setup that would give you any tipe of big gains. Fuel injection is very temperamental with mods. If you start changing pipe set ups, port timing, even a open airbox. The control unit would need reprograming or a piggy back control unit. Sounds good but not practical.

This is so true.  Change an air filter and it usually requires an expensive dyno tuning session to remap the fuel tables to evaluate whether the air filter change will result in a power increase. 

A carburetor will sense a slight increase or decrease in air flow and continue to supply the appropriate amount of fuel without having to change jets.