I recently got a tubular stainless manifold for my hatch. It is made entirely of stainless including both flanges. The T3 flange is perfectly flat but the flange that meets the head is warped pretty severely. It probably has a 1.5-2.5mm bow across the length of it. When you bolt down just one side of the manifold the other sicks out at least 4mm. The manifold has been repaired before also if that might matter.

My idea to fix this without paying for it to be surfaced at a machine shop. could cutting the flange between the runners help it lay flat or is milling the only option to fix it. I don't want to use multiple gaskets or any thing too ghetto. thanks

 

Just get it resurfaced...its better to be safe than sorry, it would be easier and smarter in the long run.