MS3 Downpipe differences and cost?
 

I am getting my 08 MS3 a christmas present of a down pipe. I already have the Mazdaspeed 3 cat back.

I see a huge difference in price between the Cobb, the CP-E and the TurboXS. Can anyone tell what the differences are, if any trip CEL, and any other issues there are in upgrading?

Thanks,