2015 640xd grancoupe vs 2016 730i sedan

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Hi there
I am writing from Turkey
I'm always using the car on long journeys during the year
I also like to use fast
today I tested a 730 and I really liked was technologically
also incredibly comfortable . Smooth driving.Well
Is this car give me the pleasure of driving at high speed?
I do not know
The get with the 7-series diesel option because of the tax system in Turkey is very expensive
Is there anyone who has used both?
almost the same price as two vehicles
Which would you choose if you are ? and why ?
Thank you