Anyone know if one were to get a check engine light for removing the mufflers that come on the car and putting on a modded OEM set in it's place?

A 993 buddy of mine and I want to do some experimentation such as he did with the 993's and now the mod is known as the LPMM:

http://manmicro.com/porsche/muffler/LPMM+bypass.MOV

It's the Porsche racer i want