I think it is safe to say that this has come down to the old reco V Rebuild. Reco is do what needs to be done to make it usable, rebuild is make it like it did out of the factory or better. I agree with the miniman, if you want it to last for long time REBUILD it, if you want it to last until the end of the year or the next RECO it. I also agree that if your doing the box, you should look at the rest of it, and would even go as far to say do the entire Power Unit. Do it once, Do it right, and you won't need to do it again. Yes Doing a rebuild on an enitre power unit will cost you 4k and up, but think of it this way, it would cost you more to REBULD most other motor's. Dunno if this helped but i think that people need to know the difference when they are asking for something.
Cheers
Aaron