Remember guys, it's not all about X amount of boost. A larger turbo will make more power at say 7 psi than a smaller turbo will at the same 7 psi. Because of this variance psi or boost isn't a good measurement of how much stress is put on a motor.
whp is an indirect measurement of how much force is exerted on the internals, it's also measurable.
From what I know the general consensus is that the D16 rods are good until about 220whp or so. Some people have successfully made much more power and been fine, while others have blown their motors on much much less. It's all in how good the tune is, if it's detonating it's not going to last very long.
The larger throttle body and manifold will allow your motor to make more power over your stock parts, how much more I don't know.
What I would do is work with the wastegate spring that's at the lower psi range your looking at and also get a boost controller. Then get the car dyno tuned by a professional, tell him how much power you want to run, he should know what to do.