Hi, I recently installed almost the same suspension setup: FJ springs with 5100s in the rear and Trail Teams in the front plus 10mm topout spacers (slightly smaller lift than 5100s set at 0.85"). I am very happy with it, and it performed noticeably better than stock during my recent trip to Big Bend NP (Old Ore, Glenn Springs, and Juniper Canyon roads).
I am also planning to go to 255/75R17 next for the extra lift and capability. What exact tires are you running and/or do you recommend?
FWIW, I am currently running Cooper A/T3s in P265/65R17 and am considering primarily A/T3, ATP, Mastercraft Courser AXT (all P-metric) and ST Maxx (LT/C1). I am leaning toward P-metric because 90% of my driving is on-road, my rig is stock otherwise, and my expedition setup is very lightweight/removable.
Thanks for any advice!