I haven't done a turbo build myself, but I've read that vtec b18's aren't as good for turbo as other b18's because they're higher compression. You may want to consider swapping your pistons for ones that'll give you lower CR (only if you want to boost). According to Wikipedia, your b17 has a 9.7:1 CR, compared with the 9.2-9.4 of the B18A' and B18B's. Maybe that's close enough?