First you have to decide how much money you want to spend. A vtec engine is going to be the best bang for the buck, but can always cost up to twice as much over the non-vtec engine.

You have to think about a power goal you want, and build from there. The LS can make power, but it has to be build to make and safely handle some real power. You can only go so far before you need piston and rods, or need to resleeve the block, or the head no longer flows efficiently (as if it ever did). That's why say a B16A or a B18C makes more power lb for lb than a non-vtec. A stock B18C1 is going to handle as much power as a 'built' LS. The LS isn't very balanced, the head doesn't flow as well, etc etc...

And Spec, it is in the tune :reechy:

Also, the B20 is the SAME thing as an B18A/B. Same block, same sleeve casting and design, everything is the same, except the B20 has a slightly larger bore. In fact, everything is the same, the head, block, crank, rods, etc, except the intake manifold, and pistons.