EVO-Tech Fuel Controller

The system is designed in particular for Electronic fuel injection which is ECU governed. 

If your's is a 280GE which is mechanical fuel injection therefore no use to you. The 300GE and latter G-Wagens employ ECU control and those vehicles could be adapted for this kit. If the manufacturer claims it can be fitted to a 280GE then I do not understand how the kit could control and or manage fuelling.

Other than that,  I have no experience of or news about this or any similar kits.

Principally it sound feasible. Some concerns I would have on a theoretical point, considering engine management now amalgamates gearbox control for better fuel economy and power transfer etc; would the kit interfere with the original ECU function or is it likely to throw up gremlins?

http://www.magnumtuning.com/en/detail/evo-tech-snowmobile-fuel-controller