Debris and Magnets?

I have recently purchased a 2008 M-Sport 550i with a manual transmission. I am currently doing a lot of reading etc... trying to get acquainted with my car and BMW in general since I have never owned one.

I beleive the best way to get true value out of most things is over the long haul, through good use and good care. I intend to drive this car to well over 200,000 miles and enjoy proving the point that with rare exception a well cared for car will never fail its owner.

I took the advice of a BMW mechanic to heart. He sugested the best way to have a good experience with a newer BMW was to get one with the absolute leaset amount of miles, care for it, and it would be very dependable and without major service issues.

I got lucky and found one with only 27,000 miles and a good service history, however not many services performed with only 6,000 miles driven per year.

I am new to this forum which I found when doing research about E60 service intervals. I was not very satisfied with the information in the owners manual or with answers from BMW service advisors. I think I can get onboard with extened service intervals, but being told having just rolled over the 30,000 mile mark, that there is definitly no need to replace the origonal coolant, gearbox oil and diff fluid at this point or in the foreseeable future does not really sit well with me.

I would love to hear anyones opinions on this and have already read a few good posts from people about the topic. Regardless I will probably be draining and replacing the above myself sometime soon, There is bound to be some accumulation of material and shavings from when the car was new till now, especially considering how tight the tolerances are.

Two questions, has anyone seen on the first drain and fill an excess of debris and metal shavings? And does anyone use the oil/diff plugs with magnets in them if so what is your opinion experience?

Thanks