OBD- onboard diagnosticsobd1- for one you have a 95 civic which is obd1 so you will not have to convert to obd2, which is easy enough, you could just but a conversion harness. also easily tunableobd2-more of a learning ecu, you can make changes in its programing, but the computer will make corrections itself to return it back to how it originally operated, or very close to it.