I would personally Kswap the car if you are planning on keeping it for a few years. The B16a's are a old motors. They will requuire some kind of major service plus the fact that its a 15years old engine, you always have something in the back of your mind that something will give up or stop working. You can sell of the b16a package for a few thousands and use that towards your Kswap

K20's are becoming much more affortable. Just need to shop around for parts to make it fit the engine bay. Other than that, you cant beat the 6 speed LSD gearbox and the VTC technology. Kswap + turbo and you'll see around 350-400hp easily.