Everyone here has made some good points. You need to think about what you want to do with the car. What are your ultimate goals. And don't say 500hp either. What do you mostly do with the car. Is it always going to be your daily driver. Do you want to drag race, street race, do mountain runs, etc. Last think about how much money you want to spend.

Chooses for about $3000

1. Turbo you D-Series. The non-vtecs can easily make over 200whp with a quick spoon turbo. The vtecs can make close to 220whp. For the $3000 you can go ahead and get a good exhaust, ecu, tuning, and things like a clutch to hold the power. HOWEVER, you are at the limits of the motor in stock form.

2. B-series swap. This will get you about 150whp with the B16 with I/H/E. It will be hard to get the header and exhaust and the swap for this price. The advantage it that there is more potential for the motor down the road. Also, all motor is sometimes prefered for mountain runs and auto-x.

3. K-series swap. The $3000 will get you a K20 to set in your room and look at until you can get another $3000 to buy the rest of the parts and pay for labor.

Later.