(headgasket failure) and have been using it sensibly 
I've now serviced it again and I am using it slightly more agressively
however once the car is warm it seems to misfire in low revs in 1st and 2nd and when boosting you can hear the air leaking.
This car was set up at 1.2bar but since rebuild it's been lowered to 1bar.
Could the misfire be due to boost leak or could it be coil pack???
Once it's built boost up it seems ok but won't go over 0.9bar.
If I find the leak will this cure the misfire???
Thanx in advance
chris