Think of it this way a turbo would be a great way to go but after installing a turbo kit on a SOHC motor the next greater step would basically be building the motor however if u put a b18c swap in you would be faster than a turboed d16 at 6 or 7 pounds of boost. One of my friends has a 99 civic with a greddy kit with only like 40,000 miles and my other friend has a 92 civic vx with about 150,000 miles and beat his car since he has had 50,000 on the motor and they raced and the 92 civic kick his ass. The 99 civic pull untill my friend in the 92 civic hit 2end gear and then the race was over. So I would think of it this way the b18c will give you a better base to start from and then u could turbo it and it would be even faster. Then when u want to run higher boost you could build the b18c and make it so the a turboed sohc could never even get close to u. But ever great once in a while u might run into a car with a Sohc that might give u a run for u money but I highly dubt that will happen a lot