I came across an interesting piece of technology that I didn't really know existed I was wondering if any had cars with this in it?

Here is an good example of what I mean:
http://www.youtube.com/watch?v=ThwV-7XB-Lg

or http://www.pfyc.com/pc/GN5018/G6EXH/.html
http://www.pfyc.com/mm5/graphics/new/gn5018.jpg

Any thoughts, how would it fair in emissions testing, how does it effect the life of your engine constantly changing back pressure, etc.

It shouldn't change the emissions/testing, but the life of a engine....thats a good question!

I watched Stacy, on the TV show TRUCKS, do the something on a offroad truck about 4 years ago! Wide open when offroading and closed up when on the road.

Those have been out since the 60's. No they will not hurt the engine. It was an option on the 69 GTO.

They have been available for a long time. Used to be manually controlled the saw some that were vacuum like the on on GTO now they are electric.

it isn't going to hurt your car/engine...that wouldn't make any sense...

edit: oh, and i really doubt that it produces almost 20hp/20tq

My friend built a '96 Bonneville SSEi as a street/strip car and used a QTP electric cutout. QTP is one of the best for cutouts, but unless you're building something hardcore there's really no point. Losing all that back pressure destroys your low end torque so it just makes your car louder and slower (if it's mostly stock). If you have a huge cam, heads, etc it's great. If you do use one, make sure to put it somewhere you can reach, carbon builds up on the butterfly so you need to clean it pretty often to keep a good seal. Also opening up the exhaust that much on a v8 sounds great, on a 6-cyl it sounds awful.