I have an ATS Ported Housing and a WW. The difference over stock is completely out of this world. No comparison between stock vs my ATS/WW. I was in that dilemma myself and decided to just do it myself as I have rebuilt several turbos in my life and they are easy as pie. Getting them off the truck is the sorry beepbeepbeep part, well, the back exhaust clamp anyways. I had $85 in rebuild kit, $80 in the WW, and $420 in the ATS housing and about 4 hours of my time in the shop.
Love the combination.