If all you want from your muffler is a different sound and a fashion accessory, then you don't need the pipes. Stay 2" or less if you want custom pipes made for a SOHC.

But if you actually want performance out of your SOHC civic from the exhaust upgrade, buy the real Apex'i exhaust with as much Apex'i piping as you can get. It will fit right, be mandrel-bent, be resistant to corrosion, sounds better, and will out flow anything anyone will make for you. Sure it costs more, but you get what you pay for when it comes to an exhaust.