There's not a whole lot you can do to the GE-VVTi to make a lot more NA power. Header, exhaust ,ported head, cams, ported intake will give you some gains, but hp per dollar will be bad (but then again naturally aspirated hp/$ is always expensive).
BEAMs would be cool in its own way, but it comes in a higher state of tune than a GE-VVTi right out of the box, and will be even more difficult to get NA power out of it.
NA-T vs GTE is a wash, in my opinion. With the GTE, you have advantage of strong rods and correct compression for boost without opening the engine. You also get an exhaust and intake manifold bolt pattern that's easier to work with than a GE. The disadvantage is you pay extra for it, and most people throw the exhaust manifold and turbos away. You'll also need a bespoke wiring harness. I think the money is better spent on putting good rods and pistons (and freshening it up with new seals, etc) into your existing GE-VVTi.
$10k will definitely get your engine setup all squared away with good manifold, turbo, ecu, tuning, fuel system, etc. However, you'll still need a transmission/clutch solution. You'll probably also want upgraded brakes and suspension components.