Which of the following would you consider makes a Williams non-'standard' to the degree it depreciates the car's value?:
1. Upgrade of original cassette stereo.
2. Upgrade of speakers in door panels and elsewhere
3. Upgrade of original car alarm / immobiliser
4. Upgrade of headlights to HID
5. Extra wiring for phone / satnav
6. Upgrade of standard horn
7. Upgrade of steering wheel