I dunno Belize...that little 16g would be working a LOT harder to hit his 300whp goal than a B16g/E16g, and be a touch out of its efficiency range, which means more heat, and therefore less consistent power....and let's be real. The s16g being more efficient below 15psi is entirely irrelevent, being as he wont be anywhere near that boost level. also, having a peaky, quick spooling turbo with next to no top end is extremely disappointing. Sure you're hitting 25lbs by 3500rpm, but what good does that do you when you're only making 12psi at redline....? Enjoy your s16g's all you want, but when you're getting pulled on because your call falls on it's face above 4500rpm by a E16g car, you'll see what I mean. Plus, come accross an E16g, and you've got at least an easy 60-75 more HP to play with when (yes, I said WHEN) you get bored of 300hp.
The main reason most of us suggested upgrading the turbo, was because it's ALWAYS easier to dial a setup down than it is to stretch a setups' capabilities. It's also safer for the engine, more reliable, and more efficient which therefore makes it more enjoyable, IMHO.
Going with a bigger turbo will not only alow you to hit your goals more easily, but also give you a bit of room to grow. It's the same eal if you're running larger injectors than you "need", a larger intercooler than you "need, and so-on. Then, when you get bored with your 300whp (Yes, WHEN again), you'll have some room to play with, and hopefully it'll be just another matter of a larger turbo and fuel/etc. Spend the $$ out of the gate on things you figure you'll want to do down the road, or have in the back of your mind, and it'll make it that much easier to acheive down the road. Just sayin'.
-Jake