What are your goals for the car? Stock vs. stock the b18c1 is better. If you want to turbo then the d16 is probably cheaper in the long run. It will be costly to build up the d16, but just think of the near 2K you'll save from not doing the swap you could put into the motor. Personally, I'd get the gsr motor but that's just me. It all depends what you want it for: racing, 1/4 mile, etc.