My truck came new with the Generals and they were POS's too. They had a vibration that could not be solved even after balancing many times. I too said I would have made Michelins part of the deal had I known how bad the Generals really were.
I ran into the same issue as you when looking for new Michelins, in that I wanted the MS2's. I believe the MS2 is only made in LT245/80R17. I ended up going with AT2's which are made in LT235/80R17 because I was a bit concerned that I might have rubbing issues on the rear duals when loaded heavy. It turned out that the Michelins are considerably narrower than the OEM tires were and LT245's would have been just fine.
I don't regret going with the AT2's; they look really good and are a super quiet highway tire (my truck doesn't go off road as it's a pavement princess :B), but if you want the MS2's you will need to go to LT24580R17 and they will work just fine.
Hope this helps.
