problem solved
 

i was having problems with the car hesitating over 5000rpm and the cel light coming on eversince i brought it 3 weeks ago , after doing an ecu reset i was left with a code 22 (knock sensor) .
i purchased one today at subaru in st albans (very nice guys) and got it fitted by a friend at dp motors st albans today.
wow :luxhello: what a difference it has made , the car pulls really well all the way to the redline. it is fantastic .
i am now going to fit my z4 ecu and see what its like then :D