Dr. Jekyll Mr. Hyde?

I guess you are looking for cut-outs?

Where you can run thru mufflers and flip a switch to activate open exhaust??

I hear summit has electric ones that are medium quality.

You will need a welder or an exhaust shop.

http://www.summitracing.com/search/...s/?keyword=exhaust+cut+out&kr=exhaust+cut+out

Check out the link to some cut outs and pipes you can manually open up by "un-capping" them...