Apparently if you take the parts of the cars listed below this would be the worst car for reliabilty according to Warranty Direct - also note not a Vauxhall listed but plenty from the VAG group, Mercedes, Audi and the BMW M3 of all things 

http://pistonheads.com/news/default.asp?storyId=23932
We've printed a more detailed list of what goes wrong on what (and how this bizarre image above has been created) in the table below.
Make and Model Car part
Audi A8 Brakes
BMW M3 Suspension
MG TF Engine
Land Rover Freelander
Gearbox
Mercedes-Benz V-Class Ignition
Renault Megane Electrics
SEAT Alhambra Air-conditioning
SEAT Toledo Heating & Cooling systems
Volvo C70 Steering system


http://pistonheads.com/news/default.asp?storyId=23932
We've printed a more detailed list of what goes wrong on what (and how this bizarre image above has been created) in the table below.
Make and Model Car part
Audi A8 Brakes
BMW M3 Suspension
MG TF Engine
Land Rover Freelander
Gearbox
Mercedes-Benz V-Class Ignition
Renault Megane Electrics
SEAT Alhambra Air-conditioning
SEAT Toledo Heating & Cooling systems
Volvo C70 Steering system
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