Ceramic Coated but the 02 bung threads are messed up. I put a bung plug in it for a temp fix and relocated the 02 to the crossover (as headers do) until my new manifold came in the mail.
02 Regal GS
ZZP Headers/ 42#/ Intake/ S4 zzp sc/ Ported Lim/ LQ4/ HPT/ 3" to SuperTurbo/ Phenolic IC with 2.8 pulley/ XP/ Ported Heads
PB-------12.3 @ 110.......312hp/350tq