I swap thje manifold and cat from my 93 Civic from an 92 Civic ,the manifold was cracked on the 93 so i took the 92 manifold, Questions : 1. Is the manifold suppose to be exactly the same? 2.The Manifolds i switch ,the 92 is cast iron and boxy like the old one is oval and looks like headers. 3. Will this cause it to not preform correctly?