You want TRD Tundra
front springs.
Read this
I'd advise the Land Cruiser springs in the rear if you want a softer ride with more flex. The OME's lend themselves towards a sportier ride that excels at carrying weight.
TRD Springs ~ $80, LC springs ~$80, Bilstein 5100's ~$180, Monroe Sens-a-tracs ~$40, adjustable panhard bar ~$90, alignment ~$80.
If you haven't already, I also recommend doing lower ball joints, inner/outer tie rods, steering bushings
BEFORE installing a lift. A lift stresses these joints much more than stock and trust me, you don't want them to fail.
If you want an even more budget-minded option, I'd love to shamelessly plug my spacer lift for $125 + shipping. It rides "ok", but doesn't require any supporting mods. I still recommend doing LBJ's, I/OTR's, and bushings though.
Best of luck and remember, if you need help just ask!