ok me and lude have been talking about a LS/vtec boost, but IU am not understanding the lowering of the compression. he was saying that it runs some were between, 11:1 and 12.5:1 thats some serious stuff. I know that compression ratio is found with the equation of...
CR=PV+GV+CCV+DV                            OVER
GV+CCV+DV
what this means is Piston volume+ Gasket volume+combustion chamber volume+Deck volume

So from this the only way that I can see you lowering your compression is from a smaller piston volume, or Gasket volume (head gasket). You could also change the deck volume but I don't think that the B18B has a deck worht machining. If you guys have any comments or advice hit me up.
peace  

that about sums it up, you can either stacka couple head gaskets or go with new pisotns. You could have the stock pistons machined, but I wouldn't recomend removing material from a piston that is going to be used in an FI engine.

I don't know what the stock compression is but if it's 12.5:1(which is pretty high for a street motor) then I don't think an extra head gasket is going to get you down to where you want to be. You dan see if there are any companies that make a spacer plate for between the head and block that would also allow you to O-ring the head, or just go with new pistons.  

thanks man I just had a hard time bending my heaad around that... lol  

those  comp ratio's i gave depend on what pistonn setup you use ... like the gsr pistons itr pistons ctr pistons or civic si each set will net you slightly different comps if you want to turbo it id say get some aftermarket p30 pistons for boost... dont forget to upgrade the ls rods as well as sleeve the block of course .. good luck