My 100% stock 2011 manual made 375 rwhp two days ago at the dyno. A friend of mine here in Phoenix made 410 rwhp with a Boss manifold, JLT CAI, tune, offroad X and Magnaflow catback in the summer heat.
400 rwhp is pretty easy to get with the mods you listed. Even easier if your dyno operator is sandbagging the numbers like some do.