ATS housing and AIS, which is what I have, is very quiet. I also have dynamat. Aside from the exhaust, it is pretty damn quiet. Of course that does not include in the winter, when it is loud as hell and sounds like it wants to explode. Having said that, if the turbo has to come out for any reason, I might ad the WW2, which is supposed to spool very fast. That will give it a little more whistle, from what I am told.
2002 F-250, PSD 6-speed, CC, short bed, 4X4, Toreador Red w/ Silver accent, A.R.E mx cap, Weld Super Single II and 33s in the summer, x-springs, F-350 blocks and badges, AIC, proflaps, ITP intank mod, AirDog with 3 micron filter, isspro guages and TTM, scangauge, husky liners, alarm, xm stereo,stull 5399-p grille, centramatics, ccv mod, AIS Air Filter, Southbend CON O, Detroit Truetrac LSD, coolant filter, 203 stat with billet housing, blackcloud intake heater plug/boost fitting, reese titan hitch, fabcraft PTO cover/temp sender port, prodigy brake controller, ITP Boost Annihalator, oilguard bypass filter, Mag-Hytec rear dif, bilsteins, hellwig rear stabilizer bar, ATS housing, non-ebpv pedistal and exhaust flange, magnaflow 3.5dp exhaust, ITP reg return, turbomaster wastegate controller, and ceramic coated bellowed up pipes, PHP 50t and 80p, currently 127,000 miles.