yep, don't spend money on a header if you're going turbo or swapping. if your motor has high mileage, pull it out, get some stronger rods (i would never turbo a d16 on those pencil thin rods), get some forged pistons if you feel like it, new rings, new rod / main bearings, arp rod bolts and headstuds, and a good cylinder hone.
also a good 3 angle valve sealing job and some serious love (replace water pump / timing belt / oil pump / all seals / gaskets / etc) will help it run like new. then boost away. you'll get real tired of 4psi real quick. build it right the first time. also look into an lsd, as a turbo ff car should definately want one.
basically plan on spending more than you think, if you want to do it right. a nicely done turbo project can actually be pretty expensive. or you could do it dirt cheap like they do on
www.homemadeturbo.com . read through their project section, so you can see what happens when you cheap out. but, i do agree with them in that custom kits are definately the way to go. some of them are done nicely, some are built for under $1000 and don't last 2 weeks.
you'll need to upgrade your clutch, fuel injectors, and get some good engine managment - at very least a vafc, or ... hondata
. i'd plan on spending anywhere from $2000 to $4000 depending on how you can find deals, and how half assed you do it. i have to say it again, cheap, fast, reliable: pick two.
and don't rule out an NA B18 swap just yet. i changed my mind between the 2 at least 43 times, before finally going with the b18c1. it's not in yet, but i've very happy with the decision.