I am a bit late getting in on this thread. I just bought a used Gear Vendors kit that was behind a Dodge Cummins 4x4. It has a 205 case that comes with the kit and though there may be some shaft differences we'll be able to make this kit work with the 205 in my truck.. My 1031 gets used a lot on the highway and was doing well with fuel economy at 16 MPG until a changed my leaky IP and now 12-14 is a good day. Anyway, a friend of mine found this kit and we were able to get it bought. He is doing the install for me now and should have it up an running soon. Looking forward to having it going. The web site, if I interpret it correctly, tells me I should feel a 3.55 gear in OD. We'll see.
Their site has a price tag of $2900 for a new kit. I spoke with them and they said that local dealers can do better on price or may offer military discounts. Something to look into. If you are using your truck a lot, you could pay for this kit in fuel and wear and tear avoidance. You can find used kits on ebay and CL. Just make sure you get the complete kit with wiring , control box, etc. Wiring kits run $450, rebuilds are $6-800 so keep that in mind when buying used. They are commonly found on motor homes, big diesels, etc.