I see two possible reasons for the question. First, does the Barbarian mod which is free reduce or eliminate the need for a $300 PCIII?
Reduce the need? - possibly to some extent. The BJM gets a lot of press in the forum, but it is not the panacea that its hype might suggest it be. Yes, it's free, and that's certainly is a nice aspect about it. But as anyone professional tech knows, dicking around with CO settings without the benefit of EGA probes in the header tubes that can read the actual amount of CO levels produced per cylinder, and how they change as one tinkers with the LCD display, it's all simply a guess. A guess that may or may not be correct. Since the fueling configuration is indeed quite lean as it comes from the factory (in order to meet some fairly rigid 2008 CARB requirements), then most have found that bringing up the numbers by +5 or +7 have improved whatever drivability/low-speed surging issues may be present.
Eliminate the need? - I woulds say categorically no. If one has a need (i.e.: desire) to tune the fueling characteristic of the engine to achieve a specific goal (maximum power, maximum throttle response, maximum "smoothness", etc), or to realize the maximize benefits obtainable from installing a completely new (and quite expensive) full exhaust system, this is the purview of the PC-III. Horking around the CO settings in a blind manner the BJM procedure does is not any way to go about re-tuning the fueling characteristics of the engine to achieve specific goals, of that there is no doubt.
If you do both mods I would bet that an off the shelf map for the PCIII would not account for the Barbarian mod and you would have to rewrite or at least tinker with the map.
Absolutely spot-on correct.
If one installs a PC-III and intends to use a stock map (or otherwise does not intend to get the bike dyno'ed to produce a map custom for that specific machine), then the BJM should be un-done if it was performed.
That having been said - installing a PC-III does not mean it's absolutely necessary to go through the expense/hassle of a dyno run, even if you have different exhaust slip-ons from stock. There are many maps freely available from DynoJet and exhaust manufacturers themselves that are likely to do the job quite nicely, including maps for different model slip-ons, bikes with or without an aftermarket hi-performance air filter, etc, etc.
However, when one installs a full exhaust system and a PC-III, then I believe it's foolhardy NOT to go the extra mile and get the bike dyno'ed to produce a custom map for that specific machine and specific exhaust system. Without it, you're likely not going to see the maximum
possible benefits obtainable from that particular configuration. If you've already dropped One Large (or more!) for a killer full Titanium exhaust system, it only makes sense to do it right and plop down another $250-ish or so to get the custom map and actually realize the significant horsepower gains that may be obtainable.