Port match means exactly that...ensuring a smooth transition between the heads and the separate parts of the manifold.

The manifold is actually made of 4 parts.

If you look underneath your car (with the undertray removed), you'll see a cast section coming off each cylinder head (2 sections)

The drivers side section has an up-pipe attached (the 3rd section), and in between the two heads, is a pipe that goes in between and joins the two cast sections together (the 4th section), known as the cross pipe. This pipe is only about 32mm in diameter, and is a restriction. Gains have been found by getting a stainless one made up in a slightly larger diameter, or buying a premade one (such as the Injen cross pipe, but its damn expensive, around 5-600 bucks)

It might also be worth looking at extrude honing the cast parts of the manifold..