2000 Range Rover engine computer change

I just wanted some opinions. I came across a 2000 Range Rover for sale. Low miles, Clean inside and out. The only problem is that the engine comp needs to be changed. He told me it was because of a bad ground on the passengers side. He had found a used one for $20 0dd dollers he said. He is asking $2500 for it. I know this means reprograming to the vin on the car. I might take a chance if it was $1500, but not sure about $2500. What do you guys think?