Whatever you do, don't buy a ceramic header. Everyone I know that has them has had them crack after about 2 yrs.
The biggest advantage of aftermarket header when you already have the EX 4-2-1 design is actually weight savings. Our cast iron headers are very heavy. The SS tubular headers are much lighter, but also louder.
I am planning on keeping my EX header and having a muffler shop cut off the restrictive 1.7" collector and replacing it with a 2.25" or 2.5" collector.
btw - all aftermarket accord headers have these restrictive 1.7" collectors as well so you can't get rid of it by buying a DC Sports or sumthin else.