IMO you can't just buy these sorts of BMW models and expect them to keep going reliably at almost 15 years old, they were iffy new and waaay iffier as they got older. Evidence of what you'd be up for maintenance & repair wise is all over the internet. Not to say you wouldn't enjoy having one but to me there are more cons than pros.
There is a big difference in buying a 20-40 year old E24, E28, E30, E32, E34, E36, E39 given the way they were built at the time, a lot of those models keep soldiering on with typical maintenance only. Peak of design simplicity, quality of manufacture and ease of servicing meant they will keep going too. These newer generation models are not the same.