Here is an update.
I have made a video of one of my typical runs so I can compare it directly to yours.  I have just been concentrating on the first sector as that's where a majority of my time is lost.  When I first started I was 1.7 secs down and in the video I am now only 0.3 down.
I have also studied some of your later set up videos for Barcelona with other GT3s where you talk the viewer around the track.  I also enjoyed your video on comparing softs and mediums here as well.
So far my conclusions are:  You are a great driver and tuner 

 and I am losing front end grip.  My mid corner speed around turn 1 and especially around the second part at turn 2 is 10% slower or just over 8mph and the car tends to run wide here.  when you are at full throttle I am still only at at about 70%  The funny thing is I can seem to pull some of this lost ground back again and the split is getting less.
It is a pity your video (unlike the others you have made) doesn't show tyre temps as I would find this very interesting.  It seems to me the harder I try, the more I overheat the left tyres and the slower I go.  A typical catch 22.
So I do realise it is down to me as both you and Stotty using your tune have proved it is doable with this tyre model and current physics.
I have tried medium tyres and the temps on these stay great BUT they are a little less grippy and so the lap times are the same for me.  I also tried loosening the the Coast setting on the diff too without any success either.
I will say one thing, gee I know my way around this track now 

  So I am still plugging away and not quite yet defeated.  I was hoping to get all these events knocked over this week as I am away for 3 weeks and when I get back we will have new updates and I will no doubt be a little rusty.
So 
HavanaB0B thanks again for you videos, help and support. 
