no mod , no cutting , if it wouldn't have fit I wouldn't have put it in because I am no mechanic.
the 88 went on the cradle the same as the 87 came off.http://www.fiero.nl/forum/Forum1/HTML/089015.html
my build post shows me replacing the duke.
the only difference was the oil pressure sending unit which I left the 88 on and changed the hookup
on the wire harness to accomadate the change from the 87 which you can no longer get.
bad pic but you get the idea.