housing imperfections

i have a big 16g that has about 15thousand miles on it. when i put a new manifold on my car i noticed that there are a few minor imperfections inside the housing right where it meets the manifold. they look like very small scratches and dont seem to be more than 2mm deep, but i was wondering if this could cause a problem.

Not unless they penetrate and become a leak. Keep in mind that it's more prone to cracking there because it's already weakened.

Port it, get rid of the cracks, and increase exhaust flow all at the same time ;)