well, stock it is only 130hp - due to the additional 100lbs or so that you will be adding with the B18 engine, tranny, etc. the stock engine is not going to be much quicker than your Si - unless you convert it to LS-VTEC, it is kind of a dog - there are several D-series engines that make just as much power, and essentially bolt right into your car without having to buy the transmission, mounts, shift linkage, axles, etc. required for the B-series engine - some of those engines are the JDM D15B VTEC, JDM SOHC ZC VTEC,
JDM DOHC ZC non-VTEC, USDM D16Z6 VTEC and USDM D16Y8 VTEC - these all have 130hp and don't add any weight to your car, except for the DOHC ZC which adds less than 15lbs.