not trac bars...but the rear TRAC bar behind the axle that handles the left right angle of the axle. The rear Drag link bars that make sure your wheels do not come too far forward or backward may need to be extended a little when going with larger than 33" tires. But, they are fine for anything 33" and smaller.
OME 912's only allow for 2 1/4" to 2 1/2" lift...Calmini lifts it 3 inches and if you have the extra stiff shocks you have a really good ride. Although I'm sure you could buy the OME 912's and then the coil spacers, but when offroading such as I do the spacers fall out when I achieve max articulation( I have the sway bars disconnected). Even now I probably should wire my springs in place so when the axle articulates maxed out that the spring doesn't pop out and then jam the wiring harness that is close by. Swordy had that happen and it costs like a grand to fix.