i have a bmw318i se, i was recently on the M8 just outside Glasgow at 3am heading 4 the airport wen i decided to see wot the car could do, i was dissappointed at a pitifull 126mph, is this normal?

Do you want the bad news? Your speedo was over-reading, as they usually do. The top speed of a '99 model 318i SE was 123mph, for a manual, a bit less for an auto.
It's only a 118bhp engine in a fairly heavy car, so for it to show 126mph on the clock after 8 years wear & tear isn't too bad.