Okay, here are the results we have all been waiting for but before we start I would like to address the question of lifting off before 80mph.
I took advantage of the sunshine this morning to accelerate right through to almost 90mph on each run. This is foot firmly on the floor with the gear box in sports mode. There was definitely no lift off.
I get back and look / listen to the footage and it does sound like I lifted. I can assure you that I didn't. This also confirms my belief that I didn't lift on previous runs either.
Although there may be a lack of scientific rigor to these tests I am happy that the overall results give a good indication of the way performance is affected by the various modifications.
https://youtu.be/fARuk-nx3Pw