Thank you Planman. That is the info i'm looking for. I did forget to mention that his Jeep is an unlimited. I'm trying to convince him to stick with 35"s and the 4" teraflex full flex lift.
If he does a 2.5"-3" lift with 35s, he can skip:
rear upper and lower adjustable control arms
front upper adjustable control arms
hydro assist steering
chromoly axle shafts
rear swaybar relocation
welded in front axle sleeves
welded in front axle gussets
welded on front axle truss
welded on and custom cut rear frameside trackbar bracket
rear tire carrier beefy enough to hold a 135 lbs+ spare
aftermarket and/or reinforced front and rear axle side trackbar brackets
It will handle better on the street and go 90%-99% of the places he wants to wheel.
Then with the $6,000-$7,000+ savings, he can buy a used TJ or YJ on 1 ton axles and 40" bias ply tires with an Atlas transfer case and full cage trail rig on Pirate4x4.com.
There would be even more savings if he was considering a long arm.
If I were to do it over again, that is what I would have done.
Like eMetal says, it depends on what he wants to do.
If he wants to beat the shit out of his daily driver by taking it places that still have some sort of challenge for a rig on 40s--or if he is building it for show--then he should build it on 40s.
If he wants a great daily driver and weekend wheeler but doesn't want to beat the shit out of it, then he would be better off spending the same money on a dedicated trail rig and build his Unlimited Rubi for 35s.