question about ECU

what is an ECU upgrade and how much does it really enhance things? is it available on the IS300? if so, where could I get something like that?

thanks!

--krazy8

there are no proven ECU upgrades (like JET chips) that work... people that have had them done have had less than desirable effects. The only "upgrade" that I've seen to work is a piggy back ECU that alters your A/F ratio like the Apexi S-AFC or the ones that come w/ the SRT & Area 51 intakes.