There wouldnt be, unless somebody is running a lap record pace.
I would be willing to bet a paycheck, if somebody runs 1:30 lap times on a '14, they will run 1:30 laptimes on a '15.
There isnt anybody on this board (myself included) who could say their lap times or race finishing positions are being "held back" because they are on a 14R instead of a 15R.
Sure, on a spec sheet, it is relatively easy to point out the differences. But in the real world, the only true thing that might make a difference in lap times is the auto-blipper. And even that is a stretch because while downshifting, you are braking hard (which has to be done whether you are pulling in the clutch or not). The auto-blipper frees up a little concentration, but it isnt necessarily faster. It is just easier. You still have to brake at the same spot.
On every track (except the ones with really long straights), my lap times on the R6 are within a 0.5-1sec of my lap times on the heavily modded RSV4.
I have been a member (or Moderator) on many motorcycle forums since 2007 and been a track instructor since 2008. It is impossible to count the times i have heard or seen someone "upgrade" to a bike that is 1-2 years newer and has "better" parts or more power (on the spec sheet), only to go to the track and run the EXACT same lap times...i mean down to the tenth. Of course they can always justify their purchase with reasons in their head, and the placebo effect is VERY strong with motorcycles. So as soon as they ride the bike they are going to come with all kinds of things it does better or faster etc...because they need to justify their purchase. But the lap timer doesn't lie (which is why we ALWAYS see people giving opinions on one bike vs another...but we NEVER see somebody posting actual lap times).
Unless somebody is winning World level races, the rider is ALWAYS the limiting factor.