FWIW
Not sure that the 912s will get you 3". The 919s are the tallest and stiffest (well, the 929s are stiffer, but they are shorter). I have 919s on both my zus, with no spacers, and I got right at 3" of lift. 13 or 14 turns on the Tbars, and away I go. I have not busted any CVs (until I installed the locker, and they were aftermarket CVs). I also never tore a boot, until I swapped in garbage mecatech boots.