I don't know much about your engine but, with most EFI engines, the FI ports are in the heads, your heads either are plugged here or have nothing there. You'll either need to drill, or get new heads (more likely the latter).

Other than that, I like the way you think. Trying to get an increase from the same engine that's probably served you well since you've had the car. I like modding myself, in case you can't tell by my posts