I would reccomend the P30 pistons, and a 1 layer headgasket copper sprayed, I have done it before and it yeild s a great compression on a LS. And the LS motor suffers from Low compression, compared to its VTEC brethren, with the added Compression and better cams, and better breathing Intake manifold, it will move.

Basically the LS comp. ratio is around 9.5:1 in stock form. With the P30 pistons, and 1 layer copper sprayed headgasket the comp. ratio would jump to 12.1:1 which would greatly benefit the LS motor, especially coupled with Cams, Better flowing Intake manifold, and Tuning. It would be a beast. That is my .02 cents.

Here is a link to experiment with B-series Comp. Ratio's:
ZealAutowerks - Honda Compression Calculator

-Braxton