id get an extra thick one (1 peice) , i thinks you wanna different fuel regulator to allow more fuel through you could get a different sort that worked on boost pressure rather than vacume, so on boost she squirts more?? the 5th injector thing was onyl used on the old mechanical fuel injection/k jet?? which turbo technics did theres on?? i did a turbo technics conversion on an old xr3i many years ago, that used the 5th injector method, but i had to reduce compression ratio with a custom made head gasket to run any kind boost worthy of doing it........