SERT
The Screaming Eagle Race Tuner allows direct access to the ECU programs and their modification. We are, in affect, creating custom calibrations for specific combinations (just like H-D re flash cartridges). The Race Tuner does, however include many SE calibrations in the map files to select from. These can then be modified or a completely new file created if the combination does not match the calibrations part description.
Race Tuner provides a much higher level of tuning than any other device without replacing the ECU itself. Each cylinders fuel and ignition mapping is independently tuned, using three dimensions, resulting in a custom map that eliminates the possibility of one cylinder fighting or holding back the other.
This equals more horsepower with smooth linear drivability. In addition, warm up enrichment, idle speeds, IAC steps, rev limits, AFR offsets, injector sizing can be changed. To help in tuning or diagnostics, Race Tuner also features a data mode to collect and review sensor inputs or other data. Both of these can only be tuned accurately by using a Computer controlled load cell dyno with real time AFR monitoring.
PCIII
The Power Commander® modifies injector pulse width, ignition timing, front/rear cylinder fuel percent offset, acceleration fuel enrichment (new features being added to USB versions on-line) as a “piggy-backed” device that plugs into the factory ECU harness. No splicing is required, it does not make permanent changes to the ECU and removal returns the bike to its previous configuration.
I would say outta the two on all the info I've read on the site and info from manufacturers sites I would say PCIII. Looks alot easier install and adding of maps. Install is about 2.5 hours or so for the SERT and 1.5 for the PCIII as I have read.
Cheers!