On my 1988 4-cylinder, was able to swing the cradle+ engine down far enough to extract the transaxle through the LHS wheelwell, similar to what you say you did with the V6. Removed the LR suspension.
Did not remove the intake manifold... but did have to remove a little short piece of tubing that stuck directly out of the aft side of the manifold - otherwise, it snags on the sheet metal on the aft firewall as the cradle swings down. Think the tube was part of the PCV system, if I recall correctly.
On pre-1988 models, it might be possible to take out 3 cradle bolts and "rock the cradle" to get the tranny out - but on 1988s, the cradle is hard-mounted (no rubber cradle bushings), so you only pull the 2 rear cradle bolts, and lower the aft end fo the cradle. Therefore, it may be possible to do the job on a pre-1988 Fiero without yanking out the little tube... it's not a biggie to pull out the tube, though, so I'd just pull it. Of course, if you really want to take off the intake manifold, that just about guarantees it'll clear, with room to spare
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Good luck
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