Have a lot of customers running those sach kits without issue, including on VNT17s (brave). Was that stage 1 running R520s?
not exactly a fair comparison. fixmyvw, boraparts, and idparts have everything you could ever need for this motor and are great to work with. I believe all of them work with DBW for injector installs, also have an account with DBW and I can tell you that the distributors aren't really making much on these hot swaps.
Best to keep the tune mild until you're ready to drop money for a VNT17. You're looking at around two grand for nozzles, south bend clutch and a turbo. Rebuilt turbos can last a long time, just a matter of getting a properly built tune an doing some data logging to make sure everything behaves like it should.