the 5100 are better than the kyb's & are more geared for off roading, ive read some people say they are quite a bit stiffer ride tham OEM shocks or "light duty" types like kyb or monroe. & they cost quite a bit more & require new springs to be installed, your 140k mile stock springs are probably worn out/sagging. so all in all it will be at least double the cost of buying complete kybs, thats up to you & your budget.

as for lift, i run 265/70/17 on my 08 sport 4runner & even with the worn out 140k xreas they didnt rub anywhere, with the added 1-1.5" raise over stock from the kyb's they definitely dont rub so i dont think you need 5100s for such a small tire, its barely 1" over stock height & same width, especially if you dont go with super aggressive A/T tread. i have goodyear A/Ts that are a lot beefier than all season tires & again, no rubbing.

for the light duty you mentioned & the price difference i think youd be happy with the kyb.. if you want much stiffer shocks that need new springs & hassle of installing the springs (although its not that difficult) then go with the 5100 for double or more the cost. kyb have a lifetime warranty too & are about $100ea for fronts & $50ea for rears.