I bought a complete 1990 ex highway patrol car for $350 and it had a low mileage 5.0, 5 speed, and this rear. I'm in the process of installing everything in my car before it goes to the paint shop.
The explorer rear is definitely offset and can cause problems. There are some people getting vibration at high speed as well as clearance issues with the tunnel if they haven't shortened the one side.
Personally I would just build a fox 8.8 even though the prices of the explorer rear ends are so tempting since you get 5 lug axles, disc brakes, and usually a limited slip. The cost of doing it right and shortening one side and getting a new shaft make it so it really isn't cost effective since you can do a 5 lug swap for super cheap with the fox axle by using ranger or aerostar shafts. If you want a little wider axle, you can use sn95 shafts and disc brakes for super cheap. I see those "kits" all the time on ebay for under $200.