Ryan, that is very doable. the gears will cost you anywhere from 180 to 250 depending on what brand and where you get them from. you do get what you pay for with gears. a new posi is around $475.00. you should do bearings at the same time and a bearing kit will cost between 90 to 150 depending on where and what type you get. you can do it your self but i doubt with out expert guidance you will get it right. its best to find some one with experience. find a race track, drag, circle or road, and ask around and you will find somebody who says they can do gears. or you can find a professional shop to do it.
I'm with Scott, let him enjoy the gears!! FWIW, I also run 4.11s with a 28" tall tire and hit the freeway for car shows all the time. Rins around 3200rpms at about 60. With the cak etc it is actualy quieter at 3200 rpm than at 1600 rpm !