Well done GEE thats a exelent result, I managed 265.5bhp with my 330's, thats a good increase with the 550's. Id say tweek that boost to try and stop it dropping off, get it mapped for V-Power and get those cams and porting done and possibly raise the limiter 200rpm and you should be on the 300 mark.
Would be good to see someone hit 300 with a standard TD04L as iv been told over and over agin it cant be done
Keep up the good work mate