[BLSTIC]

It's a blessing because the stuff is technically there to get the best economy. It's a curse because you can only get incremental improvements over what's there (without altering factory goals). It's not like cars were ever programmed to use more fuel for no reason (once they got the programming ability, which I would say was a late 80's thing), so you've got to figure out *why* it's running too rich or too lean there. It's like: Why run 11:1 air-fuel ratios at high load? It costs power, uses fuel, and doesn't add to engine safety... Oh wait I have cats and they overheat after 30 seconds without the low egt made my running rich.

Sequential injection can only get so much when you're not running massive injectors, and injectors have only improved so much since, especially for two-valve heads (four valve heads now have injectors that have two-cones that point at each inlet valve and timing so that at low loads they can put the entire charge through an open valve)

Spark control in the aftermarket basically hasn't changed since the late 80's so you get screwed over with not being able to use the dual-knock sensor with 4-method closed-loop spark control factory cars got around 2005. There's one Australian car which has an increase in high load torque of about 7% by running premium fuel simply because its spark management and knock detection is so damn precise. No such luck for the aftermarket. Program your ignition, have a knock sensor if it pings, no real continuous octane detection and optimisation.