I read quite a bit of posts and articles about choosing a catback for my 98... one thing that I ran across numerous times is the formula of:

X-Pipe - catback with Straight Thru muffler design

H-pipe - catback with offset muffler design

That was the main reason why I veered away from the Mac exhaust and went with Magnaflow with the Magnapacks. And as you can see from the pictures I posted.. can't get much straight through than that