Expect £300-500 off the Lexus main dealer example.
The ACC/PCS is crap in older cars anyway, wouldn't buy a car just because it had that. Its just about getting there with new cars.
Sunroof depends on personal preferences but again, probably wouldn't pay £2-3k more for one. If there was a £1k difference providing everything else was the same I'd get the silver one but Id be opting for the blue one and just slapping a Lexus extended warranty on it