I agree with Chris. A cat is not much more of a detriment to flow than a screen door to a summer breeze. I highly doubt that there are people that can 'feel' the difference. You'd probably get as much performance increase by chucking out the back seat and the spare tire.
Also, regarding this topic, I've noticed some posts where complaints were made about muffler shops not wanting to remove resonators. The deal is that while the EPA hasn't come out and directly stated that the downstream system couldn't be altered, they do discourage it. (The reasoning is that if the backflow pressure is altered, the cats won't 'light-up' as quickly.) What that means to a muffler shop is that when Billy Ray Joe Jim-Bob's Custom Muffler shop on the other side of town gets busted for removing cats, everyone in town gets scrutinized (let's check 'em all while we're here.) If they find any 'hard' violations (such as a core tag missing from a defective cat) they will start looking into 'grey' areas also (the more violations found = more $$.) The shops that will be more adamant about not altering systems at all will be the franchises (Midas, Meineke, etc.) as they are taught this by their corporate trainers.
I'm blown away by the amount of money that people are willing to spend on custom exhaust, etc. A muffler is just a giant beer can with a couple baffles. Cost to manufacture approx. $6/avg. They're kinda like Coca-Cola, the product is nowhere as valuable as the marketing and the paper cup it's served in. If you're going to keep the car forever then maybe stainless is a viable solution for you, but do the math first.
I guess while I'm still up here on my soapbox *S*, y'all need to realize that the trannys do have a couple problems that can be reasonably avoided (or delayed) with a cooler, filter and synthetic fluid (reasonable driving style helps immensely also, but who am I to talk?
)The price to repair one isn't all that bad considering that it's AWD. Shoot, I bet if you priced a replacement for a current FWD Acura (just grabbing a name from the top of the list) it would be equal or higher. Be glad you don't own a FWD Chrysler product, most of their dealers have at least three or four transmission techs in order to keep up. I also vaguely recall seeing a 'mods' list or two stating fancy air filters, blue back-up lights, etc. and then the tranny cooler was on the 'wish list'....
*climbs down from soapbox*
Beav