Wow, I'm late on this thread, but I'll throw in my

There are things available for this motor, but you'll have to do some sourcing. ie you can make a Cold Air Intake, but you have to get one for a 94+ Integra.

PreludePower.com will be able to help you out a lot.

They really are good motors, they just got left out of the aftermarket. They have great torque, and transmissions have tall gears, so you accelerate fairly quickly. I miss my 91 Si.