Re Routed Wastegate dumps should typically be 're introduced' to exhaust system somewhere on the downpipe. There is a 'prefered' distance (I believe 18'') but it really shouldn't make much difference. They are much quieter and preform well.
Now on my Altima, I ran an open dumptube. Loud as hell, and really took away from the sleeperness of the car. If I had to do the Altima again, it would certainly be re routed back into the downpipe.
(Excuse the dirty pre-fab downpipe...yuck!!!)