If for example you damage 2 wheels of your car on the nearside, you want them fixed because you do. The person fixing them says these are diamond cut it is going to cost £300 to fix them or I could paint your 4 wheels silver for £200 do you think for one minute motability or any lease company would even know what sort of wheels the car came with. You could have ordered the car with pink wheels from the dealer I doubt painting a set of alloys black will affect anything.