Re:what do you guys think about this stuff
 

That's just a flexpipe man.
The cheaper ones.
They are really good.
If you don't have a flexpipe in your setup you can use that. As for using it for your whole exhaust...well I think it will be a bit annoying as it will flex alot and bang against anyting in it's way if it's to long. remember it's a flexpipe.

Re:what do you guys think about this stuff
 

i used it just for one bend...I DO NOT recomment using it for a whole exhaust setup...the thing flows pretty well, mandrel would be better, but hey, this one is HOOOOMEMADE!!!

:D