Ok, considering with the f-sport you get all the following as standard (according to the website).
Lexus safety system+ inc adaptive cruise control, lane keep assist, traffic sign recognition, auto high beam, sway warning, reversing camera, triple l shaped led headlights etc.
Add the premium nav inc 10.3" screen - £2000. Add the f-sport leather - £2000
If I spend another, extra £6250.... What other 'bits' do I get in it? An ML upgrade? Rear cross traff alert?