As someone mentioned, in most cases you have to drive the borrowed car far from home. Now imagine those fellows who 'ship' a borrowed car to Naivasha and due to their inferior driving skills, they only end up driving the car for five minutes!!! The car might end up wondering "si kama ni hivyo tu tungemalizia kwa jam ya Waiyaki way alafu tuanze kurudi!!!"
And what happens if you get to Naivasha with the borrowed car and get yours being driven there? Probably by the owner of your borrowed car!! LOL. Do you become family friends? Start a car club?
Never count on making a good sale. Have the purchase price be so attractive that even a mediocre sale gives good returns.