I don't know if this has been posted about before, but it looks very interesting:

http://www.autospeed.com/A_0883/page1.html

 

isn't this the same idea/concept as the y2k mufflers?

 

yes, but this one is adjustable so if you get a wide exhaust for a SC with a different(higher flow) mufler you can configure this thing to give you preset backpressure at low acceleration just like the stock Y2K mufler does now, so basically you get to keep this stock performance feature when you get a bigger exhaust.