An oldie but a goodie, the A’PEX-i Power FC was one of the OG stand-alone fuel management system. Back in the day 3rd gen RX-7 guys swore by this set up although this isn’t just for wankel heads. If you know what you’re doing or if you know someone else who knows what you’re doing the Power FC can really optimize your car’s performance.
Now a days you can still get this set-up for the Mitsubishi Evo and a few others. If you’re shopping for ECU solutions the Power FC is more than worthy of your consideration.