Just done 4 timed standing starts to 60, 2 with xtra pwr on and 2 with it off.
All 4 runs hit 60 in 9.9x seconds (I think the Speedo is out quite a bit hence being quicker than the book speed as I doubt a decat would make a second difference)
So xtra pwr seems to do nothing for standing starts except make the petrol gauge go down quicker - which this car has no problems with anyway.
Anyone else have any thoughts on this button as the 300 boys seem to think its a form of magic which drops a new engine along side the original one.
To me it'd be better to reduce the weight by removing the button for the extra gain!