A friend (no really) has a TF Magna with 215/55R16 Tyres.
Would it affect the car if they put 215/60R16's on the front with 215/55R16 on the rear?

it might put the speedo out a little bit - not sure if it would be too bad, depends what size is standard for that car.
If the tyres are too big, then putting them on the back won't affect the speedo and should be "safer" for getting hassled, unless they look like stockies on the back and Mr Plod doesn't know the difference between a Magna and a Commodore. :)