I was wondering what diam size is on the OEM exhaust. I posted this in the technicl section and got one response and the person taught it was 2.5" diam. Is this correct???

Next I would like to know if the stock exhaust is enough to handle the extra air flow that Iam getting with the spacer.

 

2.5" diameter sounds about right...

 

How restrictive is the stock exhaust?

 

not that bad.. The cats are though.