i own a x3 2005 2000cc petrol

i have done 200ooo km up to now

the last days i have noise and vibration starting from 80km and up,does stop anyway
i use the standard wheel and tyres the manual recommend all time

so where do i start ??? bearings wheels rims ???

the noise comes from under my seat and also the vibration is noticeable through the steering wheel

thanks for the coming suggestions

i hope i m not the only one having this problem