You can balancing all the pieces, if you pretends exceed or go to the top of te engine OEM limits, breacking the OEM rev limiter, in 4 L engines, it balancing independient, chec the piece oem...
I have thís pulley and alluminium flywheel, clutch stage 2, without any problem two year and arround 25,000 milles...
The crank oil seals gone in a excelent condition, mabe these pieces are the firs piece damaged, but is'nt happens...