Two piece rotors are 4 lbs lighter per side. So 8 lbs of unsprung weight off the front end.
Thanks so much Andy! Unfortunately the 2 piece rotors and shipping to me would cost nearly $120 bucks per pound so the price is hard to justify as Cass's Stage 4 kit works great just heavy. I also have a spare set of his 1 piece Mercedes rotors already. I would rather spend that money on more track days.
If someone were to start from scratch I would definitely recommend your kit with Cass's 2 peice slotted only rotors!