2.0 bottom end good for shitloads of power, considerably over 300. Best bet to go low comp yeah. A cheaper option is calibra turbo pistons, or a few types of forged pistons: accralites, arias etc

I'd personally go for steel rods over 270hp, its not a must but a risky thing to leave out. One thing thats definitely worth the expense, no-one wants to see a rod poking out the block

zvh won't produce significantly more torque no, but will show a proportional difference with the gap between hp and torque if you know hat i mean. With a good setup/turbo etc 170-180 easy at 7-8psi yeah, i made 235hp @ 14psi if thats any indication