i dont want dual pipes from the motor i just need new headers and a split from the cat back. i just want the look and sound of the dual

Ported manifolds (some do the porting on clubgp.com for $100+) are probably better if your car is relatively stock. (ie no cam or rockers) but if you got alot of $$ and don't mind loosing low end or plan to cam it, the best header option for a L36 is http://www.ssheaders.com/

You guys are agreeing with eachother. An X or H pipe is on true duals to even out the pressure. a split after the cat is just a y pipe.

Well some people i know are ADAMENT that true duals has no crossover at all.

However we have a single outlet from the exhaust manifold so whatever you can get to flow the most CFM is what'll give you the most HP, single or dual.

where the exhaust makes a 90* bend to go to the muffler, cut it right there and weld on a Y pipe and then dual mufflers. there is an SSEI in canada that has done this

I dunno, i still don't see how it'* 'better'

this set up works wonderfully for me

just an option

If you want a extra power boost, go with the cat-back, and a set of ported manifolds. I love my PEM'*. I gained some power, and it spiked my gas milage.

Take into account that the SE doesnt have the cutouts in the rear bumper for tips. Headers you have a few selections: TOG'*, SLP and SS headers. I would recommend ported manifolds(you can either have someone do them or buy from WPI), but if you are set on headers get the SS headers, unless you decide to really stack on some power get either the TOG'*/SLP'*.
Any exhaust shop should be able to fab up a new downpipe for you, go with a 3".