I picked up this site from The Daily Telegraph and according to
the article, many vehicles they examined have seat defects which
make you prone to whiplash injuries.
Models rated poorly include the C-Class, BMW 3- and 5-series,
Hondas and VWs, while some Nissans, Fords and Renaults passed with
flying colours. Have a look:
http://www.thatcham-sites.org/ncwr2/jsp/index.html
The site http://www.thatcham.org also contains
other features on vehicle security.