I'm researching the explorer swap myself.
It is an all aluminum motor so you get the hp increase (~ 30 - 40) and ~75 lbs off the front end.
In a 96 it would be cheaper for you, as you will have almost everything you need except for a 94/95 front cover and some gaskets (use the 96 throttle cable, fuel rails, injectors, fuel lines, intake tube, wiring harness, coil packs, EEC). So, I would estimate less than $1500 for the engine swap. This of course depends on which of the 96 parts you re-use vs. new parts. As far as being a tuff engine, ask TimB, he's got a SC on his.
Sorry, can't help on the tranny part.
02 AL PI 4.6L, 02 GT MAF and air box, SCT tune by lonnie.
2.25" true duals, no cats, Borla XS mufflers.
96 trans with 300HP + gear change J-mod, Mark VIII TC, & Hayden 30K GVW cooler.
Solid Rubber engine and tranny mounts. Polly front-end, tranny crossmember, and IRS bushings.
3.73 TL, 93 Mark VIII DS. Tokico Blues all around.
PBR dual piston calipers in front, Rear Disc Brake Swap.
97 console. Cooper 225/60/16s.
14.874 @ 93.56
with 3.27 before 3.73 upgrade