Anyone prefer one over the other? Or best to do both?

 

I have the intake on my gts. Don't really know if I notice any diff.

 

I've got the IPD Y-pipe on my '06 CTTS and can't really tell a difference. Maybe if I'd Dyno'd it. My stock plastic Y-pipe was starting to delaminate on the inside, maybe the extra boost of a CTTS is a little too much for the design.