Question about selecting the right size wheels and tires?

I'm thinking of putting new rims on my xb for the summer months and I want to put a 17in or 18in tire and wheel package on. I was wondering if I go with a larger wheel and a lower profile tire do I still have to have the spedo re-calibrated and the alignment checked? The stock rims are 15in and the the tires are 195/60 15Question about selecting the right size wheels and tires?
If the tire size is larger or smaller than the tires currently on the vehicle, the speedometer will need to be corrected when the new tires are put on the vehicle. Rim size is irrelevant, it only matters if the tires being used on the vehicle are or different size than those the speedometer is currently calibrated to operate with.