I am personally using sleepdog cat-back exhaust system. I think it's new to the u.s market. However, it is still a popular brand in Asia. If someone is looking for exhaust for his s2000, you can consider about this. It is a dual, N1 exhaust tht is made by stainless steel. The sound of it is very sweet no matter @ the low or high rpm. The most important thing is that the price is very seasonable for a well known japanese exhaust. Sorry tht i dun have the pic right now , but i will post some when i have time.
Here is the North America Distributor website:
www.nvplusauto.com

if anyone who is interest and want to know more about it.
you can email me as well or directly send a email to the company.

p.s : sleepdog not only have exhaust for s2000 but all other import cars.

 

See if you can get a sound clip too.

 

Yeah.. i've heard of sheepdog before.. they are popular in places like Japan and Hong Kong..