Not the old motor, the old fuel system. DDFI3 should be better in every way, but a lot of people were complaining about it on BadWeb. It should be more precise, more efficient, and more responsive. IIRC the stock tune on the 2008-2009 was not very good...
http://badweatherbikers.com/cgibin/discus/discus.cgi?pg=next&topic=32777&page=398826
About the motors... the 2003-2005 are notorious for spinning rod bearings and shearing crank pins at low mileage (~20K miles). Apparently, the oil pump isn't well aligned and it was causing the oil pump drive gear to sheer and cause oil starvation. If you know your mechanics you know that the #1 root cause of any sort of crank failure (at normal RPMs) is oil starvation. In 2006, the material of the drive gear was changed and this remedied the issue somewhat... but now XBs were still spinning bearings and sheering crank pins after continuous high-RPM and track use. So, Buell completely redesigned the rod mounting point with 1.5" crank pins (as opposed to the 1.25" crank pins in the 2003-2007) and a higher-capacity oil pump to prevent oil starvation AND give the engine better longevity if oil starvation were to occur. I suspect that this is also the reason that 2008+ Buell XBs were packaged with a larger oil cooler -- increased oil flow.
Perhaps a little to much information, but the point is that you and I both have the "weak" drive gear that leads to the majority of crank failures. To check this, drain the oil from your crankcase and remove the oil pump (situated just below the timing cover). The foremost gear you should see (in the crankcase) is the drive gear. It's a helical gear. Put the bike in 5th gear and spin the rear wheel to make sure that the gear is OK all 360 degrees.
http://www.badweatherbikers.com/cgibin/discus/discus.cgi?pg=next&topic=32777&page=242849
The best option would be to upgrade to the 2008+ oil pump as well, but I suspect with the increased oil flow capacity you would also need the larger oil cooler (a bit more complicated). It's also extremely difficult to find the parts now that Buell is done....
http://badweatherbikers.com/cgibin/discus/discus.cgi?pg=next&topic=32777&page=398826
About the motors... the 2003-2005 are notorious for spinning rod bearings and shearing crank pins at low mileage (~20K miles). Apparently, the oil pump isn't well aligned and it was causing the oil pump drive gear to sheer and cause oil starvation. If you know your mechanics you know that the #1 root cause of any sort of crank failure (at normal RPMs) is oil starvation. In 2006, the material of the drive gear was changed and this remedied the issue somewhat... but now XBs were still spinning bearings and sheering crank pins after continuous high-RPM and track use. So, Buell completely redesigned the rod mounting point with 1.5" crank pins (as opposed to the 1.25" crank pins in the 2003-2007) and a higher-capacity oil pump to prevent oil starvation AND give the engine better longevity if oil starvation were to occur. I suspect that this is also the reason that 2008+ Buell XBs were packaged with a larger oil cooler -- increased oil flow.
Perhaps a little to much information, but the point is that you and I both have the "weak" drive gear that leads to the majority of crank failures. To check this, drain the oil from your crankcase and remove the oil pump (situated just below the timing cover). The foremost gear you should see (in the crankcase) is the drive gear. It's a helical gear. Put the bike in 5th gear and spin the rear wheel to make sure that the gear is OK all 360 degrees.
http://www.badweatherbikers.com/cgibin/discus/discus.cgi?pg=next&topic=32777&page=242849
The best option would be to upgrade to the 2008+ oil pump as well, but I suspect with the increased oil flow capacity you would also need the larger oil cooler (a bit more complicated). It's also extremely difficult to find the parts now that Buell is done....