I already posted this in the integra forum, but i'll go ahead and repost it. You wont' gain much at all from porting your head. I did it myself this summer for free with a dremel and when i took off the head i found that it was already almost perfect.

The point of porting the head is to match the ports in the head to the IM and header gaskets. They were almost exact from the factory, but i matched them up as much as i could and also ported inside, and worked on the valves a bit. The gains i noticed were MINIMAL, it's fine if you do it for free like i did (only recommended if you have experience) but if you're going to pay for it i wouldn't really recommend it, you won't gain very much. Only do it if you're going hardcore and running out of cheaper mods to do

Oh and about the JDM engines, they're very illegal. First of all, they won't pass smog, and second of all, they are illegal because the vehicle control dept can't keep track of them. Your engine is only legal if the VIN matches up to your chassis.

Hope that helped