Car will have no manufacturers warranty...
If purchased from the EU your car will most definitely have a Pan-European minimum 12 months warranty.

Car will not be to full UK specification...
If purchased through an agency that specialises in the make of your choice, your car will be at least to full UK specification.

Car residual value will be worth less than same UK supplied model...
All cars are built in the same factory, on the same production line as UK supplied models and registration documents for 'Parallel Import' cars delivered after April this year are all declared 'New at First Registration' as are UK supplied cars.

Previous to April delivery cars were 'Declared New in GB by Independent Importer'. Therefore there should be no reason for an EU imported car having a lower residual than a UK supplied model.