Put in a 5VZ with headers.
Put in a late Chevy 4.3 V6.
Put in a SBC.
Put in a turbo.
Put in a S/C.
Rebuild the entire engine with killer parts and headwork, exhaust, etc. and spin the crap out of it.
I'm sure there's more ideas out there
I honestly don't know what the best reliable power you can get out of the 3VZ is without forced induction of some kind. I don't think you can get to 200 with bolt-ons unless you're boosted, but I could be wrong. It's only got 150 stock. Headers supposedly get you around 18 hp if you use a better exhaust system to go with it.
PS. I swapped in the 5VZ. I got about 200hp now, and I'm quite happy with it. That was spendy though...
Nobody makes a SC or TC for the 3.0, it's said the headgasket can't take the stress.
To make your truck have 200 hp you can dump the 3.0 and install a supra engine, chevy engine or supercharge a 3.4L toyota engine. Other than that, you'll waste your money trying to get the 3.0 up to 200hp.