What car should I get?

Hello everyone!
I'm on market after new motor, looking to spend around 8-9k.
Probably needs to be diesel, I'm doing about 200miles a week and planning about 3 European tours in coming months, about 4k miles each trip.
I would like to stay with BMW, currently own e60 523i se.
So far I have been looking at 320cd, 525d, 530d m sport only or maybe 730d? The only other car I might look at is Audi a6 2.7tdi or 3.0tdi.
Is there any sense buying diesel at the minute, I know petrol cars are going really cheap so maybe I should get 325i or 525i but m sport? Is there much difference between diesel and petrol in € at the end??
Thank you for all advice!!

Is the plan to buy it and sell it within the year for example?
Sounds like you will be doing 20+ miles pretty easily, so I suppose the diesel make sense! And do you need space for your European Tours? Guessing probably not if a 320cd is being considered, but might that be a bit underpowered (in the crusing a high speed sense) for your tour across Europe?

Definitely I'm going to keep the car for 2/3 years. I'm not really worried about the space as I won't have much stuff with me.
That's what I was thinking about 320cd, like the 330cd but they are almost impossible to find.
Personally I'm more to 530d but looking for all your opinions?? Will I get something decent with low mileage for 9k ??
Thank you