Upgrade!!
The cost of a trans swap is far greater than the cost of any of the high quality auto trans upgrades.
I would recommend finding someone in your area with an upgraded trans a take it for a drive. You will be amazed at the difference.
I couldn't find anyone in my area with an upgraded trans when I was in the market for upgrades, so I went with the trans with the best reputation. I upgraded about a year ago. [see signature].
I've never regretted my decision, upgrading my trans made my truck into what it should have been when it left the factory. The power is now getting to the ground, where before it was being turned into heat in the Torque Converter.
If you do a search on auto trans, DTT, ATS, Goerend, etc. You will find hours of heated discussion to read. Truck owners tend to get rather passionate about the products that they spent several grand on. And everyone likes to think they made the best choice and have the best product available. Therefore there have been several long and hot tempered threads over which trans upgrade is 'best'. My take on this is that you should find one that you like and have service for in your area.
Hope this helps Greg L [the noise nazi]