I have to replace my cat on my '99 LS as a result of bad valve seals blowing oil through the exhaust. I am putting together an LS/VTEC turbo motor to drop into the car. Is it a wise investment to get a metalic core cat or will a ceramic core do the job. I'm not talking all out race car here, but I figured the added heat might warrant the metalic core. Any thoughts or suggestions? Thanx.