From Spain, Tanger or Marrakech to Dakar - how to get a car?

[Milano]

Hello,

I'm planning a trip (4 guys) to Senegal or Guinea (depends on time). We would like to start in Marrakech or Tanger.

I was in Dakhla by car last year so I know what to expect in Western Sahara and I read a lot about Mauritanian borders so I know that it could be little bit time (and money) consuming and know about safety concerns in Mauritania.

Questions:

What do you think - how long would it take from Marrakech to Dakar by car (not 4wd)? Google says 35 hours straight so let's say 60 (reserve) / 8 hours a day driving ~ from 5 to 8 days?

The biggiest problem is a car. I don't expect that normal car rental company would let us go to Senegal. Are there any options I don't know about? My only idea is to find some Morrocan on Internet and make a deal that they sell us the car and then, on the way back, we sell them back the car for the lower price but we won't have a huge budget, maybe 1000 - 2000 EUR we can pay for car if most of them will be paid back then.

I'm open to any advices and experiences.

EDIT: I heard that you can't buy car in Morocco unless you are citizen. So maybe the option is to buy/rent a car in Algeciras or Madrid.

Thank you,
Milan