Rods + pistons + ARP hardware and a tune. I am 90% sure the 3ur is a 1piece sleeve so upgrading will be difficult. I would look into a main girdle and if possible, a sleeve girdle. See if any boosted 3ur's are taking your target hp levels and see if they needed the girdle to make it work. Also, I would bet the transmission will last a while if you install a large trans cooler(RV sized) and increase your mainline pressure. Does the new tundra use a kickdown cable? Wish I had your problems