I'm still running the stock pipe and intake. USA tune with catalyst and O2 sensor. My original complaint was the lean surge at steady speed and light throttle, especially in the lower gears (lots of traffic on my way to work). I loaded the TOR tune, and wasn't happy with the results - it seemed to lose some midrange. Didn't power-wheelie as well
. So I went back to the original tune, thought about playing around with the fueling tables, but didn't. I actually went in and unchecked the box "O2 sensor fitted" in one of the option screens, which the manual said would force the bike to run in open loop mode all the time. So it doesn't try to go into closed loop, and doesn't try to trim the fueling back to a specific air/fuel ratio. Voila, no more lean surge. So I'm happy for now, with just this small change, until I get a different pipe.