Here is my quickest lap @ Rudskogen i 2013 .   1.43,09 !
It happend on a Trackday.no event 28. Sep 2013. 
My previous best was 1.44,57.

The only difference in car spec this time was E85 and tweaked ECU tune.  I would say the added tq down low and top end gave me at least 1 sec. Most likely more as my driving and lap times have started to get quite consistent the last two trackdays.
I would estimate 5-7% more power as would be expected from E85 energy content at the same lambda value.   I added 2-3 deg more timing on top (from my tunde 98 map) and quite a lot more from 2-5.5K rpm. Especially the midrange is noticeable more beefy.
It is nice to see that such a modest power increase alone leads to better laptimes. That means the rest of the car (and driver...) is not a limiting factor, yet.