Check with John at Fuel Injector Connection. They have rebuilt, and new injectors, including their Blue Demon brand. A number of us in the Georgia Club have been running The BMW V8 injectors in our 3.4's with good success. Bosch part number 280 150 94. They are a modified pintle style injector. There's a link here:
I believe this is the injector. It should flow 16.88 # at the stock Fiero fuel pressure, so there's no need to spring for an adjustable fuel pressure regulator. Several of us are getting 31 mpg on the road, but they're running slightly lean. You may want to have someone bump up your pulse width in your chip, though I've not experienced any problems with the slight lean burn. Since you didn't get a BMW return on your search with the number I gave, I'm not positive that's it. It was on a note that I'd dropped into my file on my last 3.4 swap. Before ordering, it'd be best to give them a phone call, tell them you want this style that will give you the 17# flow.
As a comparison, I did one 3.4 with stock Fiero 15# and one with stock 3.4 17# injectors and one with these Bosch injectors. There is a big difference in performance with these Bosch injectors.