Honda-Tech - Honda Forum Discussion - Stand alone vs wide band

a standalone EMS is used to control fuel/ignition/rev limits/etc etc etc whereas a wideband is an o2 sensor used to help tune the fuel/ignition/rev limits/etc etc etc of a engine management system (EMS).

They aren't even the same thing, so to compare a standalone to a wideband o2 sensor doesn't make sense.

Now, if you're asking whats the difference between ROM editors (crome, hondata, neptune, ectune) and standalones (motec, AEM EMS, fast) then there are plenty of differences. The main one being ROM editors use OEM ecus that you modify to allow an external ROM (or chip) to be used to control the fuel/ignition/rev limits/etc whereas a standalone is a whole new ecu that you use to control the perameters.

Standalones often require changing wiring harnesses and sensors to use ones that are compatible with the standalone ecus (there are plug and play kits available though). Standalone ecus typically have more features available than ROM editors and are capable of controlling coil on plug setups, where as ROM editors are only capable of controlling setups with a distributor.

The better ROM editors (hondata/neptune/ectune) have the nice features like standalones, such as anti-lag, 2-step, electronic boost controller capabilities whereas the more basic ROM editors (uberdata/crome/turbo edit/BRE) don't have these nice features.

Basically, you get what you pay for. There are reasons why the standalone EMS's cost so much. Although, ROM editors are quite capable, i've seen cars make 800-900whp with a ROM editor.