The wider Tacoma rear with the bigger brakes is a easy choice. You'll have to swap/weld the e-brake bracket onto the opposite side. The spring perches will line up, you may also have to swap the brake lines and mount side to side. All this small stuff will comr to light once the axle is on place. The 4-runner axle will require bracket removal, spring perch install and other mods, not a problem iust more work. Taco is the easiest, I like easy and wide.
The E-locker will work in a modified front housing and stock axles, but the Birfs will puke with big tires and hard wheeling/crawling
