thanks jerryVANOs noise on cold start up is not uncommon for the S2, which is derived from your motor. If it goes away in 2-3 seconds, I wouldn't be concerned. It is simply the oil pressure building up. On the earlier M5's, an accumulator was added to prevent pressure bleed down overnight.
Not sure about the oil pump bolts, I remember something about that, but seems it was on older cars and not the M5. Can it be checked by dropping the oil pan? I wouldn't think that would be very difficult, even if just for your peace of mind.
after owning a few european cars ie, c43 amg, a few boxters, few m3s...none had high mileage. this has alway been a dream car for me as now i have 2 kids and cant go willy-nilly and spend 35-40k on cars anymore, so i kinda freaked out on the noise issue with 100k miles. your the hundreth one to say, no worries. thanks for your help and advice.