The 
  following is directly from saab cars USA and provided for your information.
  Home 
  | E-mail us 
Parts and Accessories Reference Library
  
  Date: 09/20/01
  
  To: All Saab Dealers
  Saab Service Manager
  Saab Parts Manager
  
  From: Rich Miller
  
  Code: 772
  
  Reference: Replacing original equipment tires on Viggen models
  
  When replacing the original equipment tires on Viggen models, we only recommend 
  using either the Dunlop SP 2000 or the Pirelli P-6000 in size 215/45 R17.
  
  These tires were chosen because they meet or exceed the sidewall strength required 
  for a car wit the front wheel drive performance of the Viggen. The use of tires 
  other those those specified may lead to performance or handling characteristics 
  that fall short of the factory specification and therefore, cannot be recommended. 
  
  
  We recommend changing at least both tires on the same axle and all four tires 
  when you are changing brand and model. If snow tires are installed, the same 
  tires must be installed on all four wheels.
  
  Thank you for your attention.
  
  Sincerely,
  Rich Miller
  Manager,
  Technical Services Quality