I'd agree that fitting them wouldn't be worth it for the amount of work and cost. Even the keyfobs, alarm system would be affected.
I would defend their value though. Very easy for four young children to get in and out of the car with no trapped limbs, especially in the heavy showers recently. No cringe provoking slamming of the sliding doors by guests either. Plus it's a great talking point when transporting a few colleages to a meeting. And the kids cred at school is awesome!!
Shrek