obd1 responds better to mods than obd2. i think obd1 only has 1 oxygen sensor wheres obd2 has 2. :dunno:

and in order for you to swap ecus in your 99 you need of course the obd1 ecu and an adapter harness.

www.jdmhondaparts.com
www.skunk2.com

both have adapter harnesses.