Wrong diameter exhaust spacer

I needed to move my turbonetics (ebay special) manifold out from the head 1 inch to accommodate a GT3076R. In haste I used my Cometic gasket as a stencil. The ports are now 2-3mm too big all the way around. DUMBASS!!!

Will this cause carbon to build up and flake off affecting the wideband O2 sensor or anything else? Is it going to cause turbulence that will negatively change flow? Should I port match the head and manifold?

Yes carbon will build up on the edges a little. I doubt it would hurt anything, but may cause turbulance in the exhaust. I would just port the exhaust manifold to match it. You dont need to port the head.

building another one would cost another 100.....Is it worth it?

Not if you can easily port the exhaust manifold to match the spacer. If the manifold has already been ported than it may make the flange to thin to seal if you have to port it more. Just look at it and see if it can be ported or not.

Thanks.