I just switched from an internal to external wastegate. I have the dumptube exiting under the oil pan. When it opens I really don't like the noise, does it hurt performance and spool up time if I route it into the downpipe?

 

If you route it back in a good ways back from the turbine you won't see much/any power losses.

 

Lovefab placed my dumptube fairly close to the turbine. He said it is for fitment reasons and that I really won't notice any power loss from it.