Be sure to install a proper header with 2.5" collector, I would go for the JDM 4-1 DC2R header if you aren't going to lower your car, if you lower get the Toda or J's 4-2-1 header as they both make great power but maintain ground clearance above the bottom of the oil pan. Toda header new is like 1700$ and J's around 1100$, you can find either used around 700$, JDM 4-1 250-400$ depending on condition and whether or not heat shield is included.
I always run a cat, JDM 2.5" DC2R bolts up to you stock mid pipe. Beyond avoiding the nasty smell it also makes the exhaust sounds smoother IMO and if you run something loud like the Spoon N1 it also brings down the dB a bit. JDM DC2R cat can be had used all day for 100-150$.
For a muffler I lean towards the Spoon N1, it sounds JDM as fuck with JDM 4-1 Header, JDM 2.5" cat, and stock mid pipe... it's loud but lovely. Around 500$ new for Spoon N1 muffler, should be no more than 300-350$ used IMO.
This time around I am using Toda header, SMSP 2.5" Cat, JDM B pipe with the bottleneck removed after the cat flange (There is a 2.25" reducer in the pipe) and the Spoon N1 muffler.
Friends don't let friends Buddy Club Spec 2.
Doing catback only on DC2 is a bit of a waste, do the full meal deal and actually squeak some extra power out of the feeble B18C5.
Alternatively just K swap
