Thinking about buying an E60 M5 with the V10. Any helpful owners out there?

This would be bought sometime next Summer. It will only recieve minimal mileage, and during warm weather. Anything to look out for before purchasing? Just how extreme would the maintenance costs be? It will probably get 2,500 km in a year, but I’d be driving it fairly hard. Looking at the seven speed, not the six.
For mods, I’d only be doing intake, exhaust and tune. For the price these are currently at, they are the best deal for the speed that they can achieve in a modern, stock vehicle. That’s why they piqued my interest.