Which is why I recommend a 99-00 Si b16a2, a 94-01 GSR b18c1, or the 97-01 ITR b18c5. Either those or you could rummage through www.hmotorsonline.com for JDM motors.

But it also depends on waht he plans on doing to it. Turbo? NA? track car? autocrosser?

turbo/track car do a b16a2 or a b18c1, for NA/autoX go with the 97,98,00,01 ITR b18c5

Also: as I stated unknowingly, the ITR doesn't have a b18a, it has a b18c series motor. go to the link and you can get a JDM b18c Type R motor

 

IMO id go after the b20 just for that added tq to get your 4dr moving. although i have seen some fast sohc turbo 4drs. actually saw one whoop on a b18c in a crx.