Sw20 n/a exhaust setup

As a general rule; the stock 3SGE headers are the best. From what I have heard aftermarket items harm performance. I had a 2 1/4" cat-back on my NA and it really gave a nice note without being over the top which is exactly what your fujitsubo is going to do. You could have a larger mid-pipe made up and replace the stock cat for a high-flow...however for the money your not going to see any decent gains and an exhaust note that wont be much different from the cat back.

See how you go with the cat-back. If you do decided to go the full system; go see Performance Exhaust Centre at Northmead if you'e in Sydney. They have done a few MR2s from here and their work is second to none and the owner Haks in general is just a great bloke to deal with. 

The easiest way to attach images is to use Photobucket IMO. Grab the photo's URL once it has been uploaded and then attach it via the little image icon when posting. 

Nice! If a good exhaust note is all you are after; this will be absolutely plenty. 

For a mass produced item the stock 3SGE headers are not bad, but in several design features they are not as good as hand made headers such as the Fujitsubo Super-x. 
Compared to the stock headers, these will give a small but noticeable gain in mid range torque if the rest of the system is free flowing. I currently have a set on my Gen2 NA.
 
Aftermarket cats:
Be aware that not all high flow cats are of equal quality, and although they are expensive I found that a Metal Matrix 200 cell metal cat worked best when I replaced my stock 20 YO cat.
I would recommend a 200 over a 100 that could be too LOUD.
I currently use a Remus high flow catback along with Fujitsubo Super-X headers and the Metal Matrix 200, a great combo!!
 
BTW, check out: http://www.mr2australia.com/mr2play/tm.aspx?m=109176 This set that I now have for sale was on my car for several months, but I recently bought another set to get ceramic coated and I have now fitted those to the car. (Don't need two sets lol)