i'd look for a b18... vtec would be preferred with the p72 head (gsr and sir-g motors)

this drops in realativily easily, gives a good deal more power and you'll be faster than a stock SI (vs going with the b16)

i'd suggestt looking into a turbo after this point.


if you want power "now" just boost your d-series, it's been done and you can make more power than a swap.