Your mother needs to drive a 400E or E420 in a W124 shell on a twisting road around some mountains (lots near the coastal highway) She would reword her opinion. Even a E320 would make her think otherwise,
beware - dont let her near a 500E (none I know in Pakistan tho) - you might never ever get permission to drive that thing ever again. Its as brutal in performance as it is subtle in looks.
An absolute hoot and a half would be to get a W140 600SEL (one dead one was at Aristocars for the longest time - both ECUs failed along with 2 more interior module failures) - That car is epic. 250 km/h - no problem YAWN.