I think the main problem is that our cars are tuned rich as fuck from the factory as it is. I pulled 13 percent from mine right now and have not upgraded the injectors yet. Then if you add a set of 750 or larger injectors on there it just won't work out.

Also the injectors don't quite work right under a certain duty cycle. (I would think) There's gotta be a minimun reccomended duty cycle as well as a Maximum. Lets just speak in theory right now numbers are just guidelines. If you are opening a 1000 cc injector for 1 second and spraying the same amount of fuel that a 550 sprays in 3 don't you think the air fuel ratio will be wack? I would think it wouldn't mix right.

Alot of guys I've seen making high horsepower (normally over 500) on a daily driven dsm have been using an 8 injector setup. I'm pretty sure they do this for a reason.