I haven't dug deep into a tranny yet, however what I do know is not so much who/what to stay away from, but more who to go to.
Lentech is the leading ********* on building high performance trannies. You're not quite going to need ALL the goodies like a modified SC would need, but some of the items won't hurt at all. I would source all the
parts I can through Lentech. (
http://www.lentechautomatics.com/aodhome.html) They have an overhaul kit that comes with everything you need to rebuild your transmission. In addition to that I would get a stage 1 valve body...estimated price for all that is about $800, but well worth it if you plan on doing it yourself. This will include all the clutches, bands, etc that you need. It will probably be better than anything that you can get locally. And they will help you out with any questions that you have. One key thing is a much larger OD band than stock. A very LARGE problem with local rebuild kits (I've seen this throughout the country) is that there were 3 different versions of the AOD the one for the n/a 3.8 (C-servo), one for the 5.0 (B-servo) and one for the SC (A-servo). Most rebuild shops and suppliers supply the
parts for the C-servo tranny, sometimes the B and rarely the A. My experience has been more on the SC side where a locally rebuilt (or supplied with the
parts) have failed within a year and often less than 10,000 miles. It's not the ability of the installers, but the quality of the
parts. They just aren't up to the task. A 5.0 doesn't have the same torque curve as a SC, but it would never hurt to upgrade to the
parts that are upgrades for the SC. That will effectively eliminate any concerns about the transmission failing in a relatively short time period. The rebuild kit alone is $415-$445 depending on exact tranny (Lentech will help you determine exactly what you need) and the valve body runs about $400 as well. They are a couple things that you will never live without in an AOD equiped car again!
It may be just a little more than you are planning on spending, but it's less than the $1800 for a rebuild that may or may not last more than a year. It's also better than spending the $2500+ for a built Lentech tranny (my next transmission step).
Lentech should also answer any questions you have about special tools required to get the job done.
The only other thing I think I've already mentioned...make sure the TV cable is adjusted beyond it's minimum. If you don't mind harder shifts, the tighter the cable, the better.