The lowest setting should be stock height. The lowest "lift" setting is 0.8" and goes up to 2.3" in ~0.75" increments. I assume this is the part number they gave you?
https://productdesk.cart.bilsteinus....-Y485A00_1.pdf
I can't imagine a reason not to use the lowest setting, even though they say not to... The front geometry is the same between 2WD and 4WD on the 4Runner. The 4WD's do get stiffer front springs, but that's only to hold up the extra weight of the 4WD system. I lost about 0.75" when I did my 4WD swap before lifting it back up with 5100's...
Well, almost. Here is 4600's with stock 2WD springs and a front 1/4" top plate spacers, but with a heavy front bumper, heavy skids and a 4WD swap. The rear is a bit lower due to some camping gear and a trailer:
And here is a comparison of near stock height to a ~1.5" front and 2" rear lift:
If you want cheap rear springs, go with stock 5th gen 4Runner rear springs and 10mm trim packers. Same height as OME2906 rear springs for nearly free, and they are decently stiff to match the 5100's.
-Charlie
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'99 4Runner SR5 Auto -
4WD swapped
'89 Camry Alltrac LE 3S-GTE 5spd
'17 Chevy Volt Premier
'16 Honda Odyssey Elite
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