I've owned two E53's and several other E39 E46, etc.

I would sell it. If you are dying to own one, sell this one for big money ($20k+) and go buy a used one with 150k miles from a rust free state for a small fraction of what you sold this for.

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'99 E39 528i 5-speed 130k
'06 325Cic auto 115k
'05 X5 3.0 auto 173k-SOLD
'03 530i - manual swapped - 430k miles-SOLD