Will extra injectors really screw your fuel economy?

[M@r]{]

As my Inj Duty hits 90% at times (with the boost turned down!) I figured this is next on my Mod list.  But will the fuel economy just get ridiculous?  Or does it just make a difference when you are hammering it?  

Obviously im used to 12-18mpg, but not sure I could stomach much worse.

[rx7veilside]

secondaries wont hurt u till u hit the right pedal..i have 1600 secondaries

[Grizzly]

All depends how and who sets it up for you.

If done correctly at the same power you should very simalar MPG, but if you turn the power up then the fuel mpg will go down.