B18A head really has no advantages over a B18B head at all and is not worth the effort IMO to put on, especially if it wasn't machined to be used on a forced induction engine.

You can always find an OBDII 1996-2001 Integra B18B into your car to make your life easier. OBDI conversions require harness changes and one less O2 bung, and while tuning is a little easier it's nothing that will slow you down significantly.

250WHP is realistic power figure with 8-10psi on stock internals. LS is a potent motor, and you always have options LS/VTEC down the road, or a full build.