Do not want to replace the floor but need to get it down about 2 inches
You probably don't want it lower, you'll end up not seeing over the dash.
I had some late model buckets fitted to my Pano and there were no floor mods apart from extra bolts holes.
I would suggest fitting up the bench seat runners, run a couple of lengths of tube/angle between and then fabricate some additional mounts to fit the level between the bench runners. Once you've got those mounts done fab up some adapters to suit your seats (sounds easy when you say it like that).