well the solution is simple - tell him you have worries about the front suspension and the definite amount of the upcoming bill for any buyer etc - with all that in mind you can offer him $4500 - he might say £5500 - then you can meet him in the middle at $5000 - seems a good deal to me - my car has just covered 150 000 miles and runs beautifully.
The red is nice but personally the Topaz Blue is the one to have