First, Steve and I live nearby and have bantered theory and practice on a few occasions. Most of the time we're in agreement (he really knows his stuff), but I see this differently.

Stock bikes suffer from a few performance tuning shortfalls due to EPA emmissions testing.

One shortfall is restricted air and lean jetting (to get past EPA). Many "un-cork" the intake and run richer jetting (V-Twins seem to like it a little on the rich side through much of the RPM range)

Another shortfall was done by the factory to off-set the above. They retard timing so they can run those lean jet settings.

Correcting the jetting without advancing the timing (preferably to the maximum possible) does not achieve full tuning potential. Running any motor short on timing advance deprives it of a complete "tuning symphony". It works best when it all works together.

The benefit may be subtle to many (more noticeable in "mid-range riding" as Steve mentioned) but I notice it. Well timed and tuned engines are more responsive and crisp (and maybe run a little cooler).

The way I see it; if you've gone to the trouble of intake/jetting mods, completing the effort with suitable timing adjustment makes sense. And that means a Dyna, set one (maybe two) settings over the "factory curve".

The fastest internally stock R* Steve and I have seen (dyno'd a "real" 75hp) runs an S&S/Nemesis intake, Pro-pipe and K&N; pretty common.

What's different is a Yost power tube (Bob Yost convinced me, who knows??), a VOES switch and aggressive Dyna settings. It runs advance right on the edge, so if the bike is two-up, pulling a hill with thick air density, it pings.

This bike (it's Jimaray's) pulls very strong on top. It ran very differently before the VOES switch and aggressive Dyna settings. I could outrun it with an "under-piped", stock carb'd, BAK'd and well-tuned bike. Not any more.

Reasonably, bike to bike run-offs can be inconclusive due to many variables, but there was no question of before/after improvement on Jimaray's bike. I think most of the gain was due to timing. (there's a whole other discussion concerning TPS/timing alteration)

Nonetheless, I think the Dyna finishes the job on tuning mods and what it does for timing advance is more important than the rev limit. (Although, better tuned motors hit the rev limit faster, so increasing it is very desireable)

Jim