Exhaust advice

You could just buy the mufflers, but most likely your exhaust is 2.25". Therefore the only improvement will be sound. Save for a good 2.5" cat-back.

Find someone that has one and SOUNDS like what you want yours to sound like. Then get that one. Nothing more disappointing then getting something and not liking how it sounds after. (I sold my magnapack kit because it was just too obnoxious. Yes, I'm old...)

Do Both

Def. do both at the same time. I just got my catback (flowmaster American Thunder) for 320 from summit. Thats with stainless pipes. I could have gotten regular for 240. The mufflers themselves are like 70-80 a piece, and then you have to weld them in. Also, your h-pipe will be 2.5, so it would be better to have your exhaust the same size instead of the stock 2.25.

Get the 2.5" Cat Back. Flowmaster American Thunder for the rumble, or three chamber for a bit quieter rumble. Throw in 2.5" electronic dumps in between the hpipe and cat back for a whole lota fun.

I would do an H-pipe before doing the cat-back after seeing the differences first hand. The stock exhuast with no H-pipe sounds pretty decent.