Troy, your dilemma seems fairly easy to solve for.

I suggest you do the conversion and add Jamie's Hemi Overdrive conversion to you current 833. This will allow you to keep your 4.10s and still allow for highway cruising.

Spend a little time on his site to look at that option as a great stop-gap until your 855 is ready.

The last piece of this is for you to sell me the GV unit for my Satellite when your conversion is complete