what are my chances on this install

Have you changed gears before? I have only seen a few people do it, and you need a special tool I believe. I would just have a shop do it if this is your primary car, or at least have someone help you that has done it before.

Your chances are essentially 50/50 that it'll go back together and be right on the first try.

Why take the chance? Install kits arent overly expensive. I would much rather have the good feeling that everything is nice and new than the gut feeling it could be noisy and not right ten minutes after its installed. Then unless you are doing it all yourself, it just cost you more money in parts and labor. Just my Opinion

If this is the first time you've swapped rear end gears I almost guarantee that it will fight you. First off your new gears may need to be shimmed differently than the gears that are currently in your car. So an install kit is a must. Their is also several things that could go wrong during your install. The pinion shaft has a tendency to get stuck. Especially if your car has been abused. When I did the gears on my Mustang it was so bad that I ended up taking the entire differential out so I could get the shaft out! Also the pinion shaft lockbolt can break off in which case you will probably have to cut the differential housing to get the bolt out! It hasn't happened to me but I have seen it happen. The crush sleeve can be a pain as well especially if this is your first one. Other than that you will want a dial indicator to check your ring gear for play. Experienced techs can do this by feel. I haven't done enough diffys to be that good.

IF you want to go ahead and tackle this project their are dozens of people on this site that will help you but I just want to let you know that it might not be as easy as you think.

I watched a pro do it on TNT a couple weeks ago. If it is your first time I could guarentee it will not turn out right

All you really need is some prussian(sp) blue and a dial indicator with a magnet base as far as setup. Get the install kit too. Bearings, seals, shims, etc. Cheap!

They are easy especially if you run the Ford Racing gears I always have good luck with them.