Steve,
I asked Roaring Forties the same question. Robert Logan emailed a picture to me showing cats installed on one of their cars. I may still have it on my email at work; I'll take a look tomorrow.
If I have to go with cats for emissions I'm considering making my own exhaust. I thought I would start with a pair of Mustang shorty headers (easy to find and inexpensive), a pair of generic aftermarket cats, and a pair of short round mufflers (small glass-packs or Super Trapps). I'll connect it all together with off-the-shelf pre-bent and straight pipe. I figure it doesn't have to look pretty considering the length of time it will be on the car. /ubbthreads/images/graemlins/wink.gif
The emissions subject has been discussed frequently on the FFCobra forum. Within the Cobra community, I haven't heard of anyone here passing current emissions with a carb although I don't suppose that means it can't be done.
If you end up going with FI, you might consider the Mass-Flow system from Quality Roadsters. It is a MAF EFI system that has a custom throttle body designed to look like a 4 bbl carb and it's a lot cheaper than a stack system.
BTW, Factory Five in Wareham is having an open house of sorts next weekend (Moochfest). This may be a good opportunity for you to talk face-to-face with a lot of guys that have been through this already, and as a bonus, check out some cool cars and get a free meal (that's why we call it the Moochfest /ubbthreads/images/graemlins/grin.gif)
Charlie
