I have an 84 SE that have had the above changes done to it.
It is now sporting a 88 Formula front and rear bumper and an 86 GT Fastback clip.
Only thing is that it is in 5 different colors. I will rectify this problem over the winter. 
I don't have any pics of the car but I think someone who was at the Red River Ruckus might. Maybe they could post a picture or two for me.
I know FastFieros has some pics of the car but they are during the transplant stages of the work.
I agree, the coupe bumpers (87/88) look pretty good with the fast back clip.
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AIM - SWags2933
84 Fiero SE, Custom Hybrid (Updated to 88 wiring throughout, V6, 5spd, Fastback, Formula bumpers and Held Suspension) New wheels and paint are the next step.
84 Fiero IMSA Widebody (Centerlines, 3800SC & T-tops being added) slow work-in-progress