I used to think my D16Y1 Civic was super fast...even scared me a little!
In my opinion do the intake, header and exhaust because they're nice. My brother's DC4 has a generic CAI, XForce 4-2-1 header, Magnaflow cat and Fujisubo Power Getter - goes very nicely indeed. I've tried to convince him to do an LS/VTEC swap and not too long ago I had a spare complete JDM B16A head but he didn't want to spend the money on it.
I wouldn't bother with a B18C2 when for only $2000 more you can get a B18C7, which has a better gearbox and produces better power.
Anyway, any intake/exhaust modifications can be used on another B-series engine later if a swap is done.

