Hmm, that looks like a 4-1 header, good for high end output. Your link led me to look at Summit again and I found this
A 4-2-1 header should be better at low and mid range power. It's ceramic coated too. It's almost as expensive as what I've seen the DC Sports header listed for the 240SX though.
At the Acura Integra forum I used to post at there were quite a few claims that the Pace Setter headers performed worse than the stock manifold as well as being poorly made.
I'm going to contact DC Sports and see what they have to say.