Hi there, I think something is wrong here! You say you have had the car RE-MAPPED and now after the remap it is only producing 284bhp???
That figure is what the car should be producing from standard! After a remap it should be producing nearing 340BHP and 700Nm torque and let me tell you the torque is unreal. I did one of these for a forum member not so long ago and I also had a 335D in last week. I think you should maybe go and pay another visit to your tuner and have a chat.
Hope this helps you.