Motec M84 is a very nice choice too a bit on the expensive side but the datalogging and data output plus Widband functions are probably worth the extra money.

AEM is a good choice as well would have to get a obd0 to obd1 or 2 converter harness to make it work.

Would steer away from any of the "OLD" Halltechs the few that i have delt with were a PITA.

Hondata is probably the best choice but would require a OBD1 ECU and a 93+ Distributor along with the adaptor harness or connectors. You can get new connectors with wires for around $80 if you dont want to go the converter harness route.

There is a TON of info out there on Honda ECU's and what is needed to make the 86-91 work with a standalone.