Hi, as a rule of thumb when you consider a tyre upsize apart from maximum permissible deviation rule of 2%
Important is to consider a size which should not exceed the defined RIM Width too
Stock Alloys are R18 7J - which means that tyre profile of R205 to R215 is what recommended, with maximum permissible deviation upto R225 Even if you replace alloys to, R18 7.5J - still R245 section tyres would be misfit in it
For all standards - R245 section tyres would be too wide and will even come out as odd alignment from defined tyre area too, adding on can impact suspension in medium term
R18 225/55 is the maximum upsize can go ahead with this car.
Hope should help !!