[SnapOversteer]

How do you know the tuning is the same though? Isn't that like saying the Altima and M35 have the same engine, and the 06' M35 is listed at 280hp under new SAE standards, so the Altima is actually underated?

You're comparing a FWD VQ to a RWD VQ, which are not the same. It's just like comparing the FWD 2GR to the RWD 2GR. Manifolds and such are often changed between transverse and longitudinal setups, as well as tuning. RWD can hold more power to the wheels.

So here are the maximum factory ratings:

FWD VQ: 270hp/256lb-ft (2007)
FWD 2GR: 272hp/254lb-ft
RWD VQ: 306hp/268lb-ft (2007)
RWD 2GR: 306hp/277lb-ft