Ha, on 1989-1993 "C" Bodies I am an expert, but on the current crop, I am as confused as a couple of the salesmen I have spoken to.
www.kbb.com has a built-in feature that if you enter 2 items that are NOT allowed together on the same car, it will tell you that you need to make a choice. But entering the Performance Package AND the 40/20/40 seat, in Tehama Leather, doesn't bother it, and it allows it. I asked 2 salesmen and one sales manager and got 3 different answers. I went to
www.cadillac.com and priced it out with the Performance Package AND the 40/20/40 bech in Tehama Leather and even the Caddy site allowed me to do that.
So, I have no clue regarding Level II and Platinum Edition. Reading thru the Platinum Edition, I just don't see alot of value for the cost. The only item there, that I would like are the illuminated door sills upon opening the doors, and they CAN be installed at the dealer "aftermarket".