I dunno about this. The lift kit sounds shakey. Just putting in spacers and the like increases the torque on the mounting points and likely weakens the overall strength of the system. Given that we're working with a unibody system here, I think that could be a Very Bad Thing at the Absolutely Worst Time.
IIRC, most quality lift kits actually replace the majority of the suspension and steering components with their own properly engineered parts. On top of that, some of the larger lifts require changing driveshaft geometry to prevent binding of the U or CV joints.
While this was likely a cheaper way to do it, Jeeps (even used and basically rust free) aren't that expensive. If you really want to have that ghey of a body style, but the Jeep and adapt the body to fit on the frame. Or purchase an old AMC Gremlin and an IH Scout and put the Gremlin body on the Scout chassis. I do believe everything actually lines up perfectly.

Actually, the Fiero is (IIRC) a space frame design, not a unibody. The body panels are not structural, and can be replaced at-will with simple hand tools. It's actually quite a strong system, and was thought to be a real selling point of the model. Unfortunately it was an expensive, funky looking car that GM didn't really know what to do with, so it never (again, IIRC) sold extremely well.