Question about tires

Jhon Snow

as you guys know the car comes with these tires (with sports package):
245/40WR19 (front) and 275/35WR19 (rear)

I would like to cheaply increase the minimum ground clearance just a little bit (by about 1.1" if my math is correct), and i was planning on doing this by changing the tire size from the standard ones it comes with to something along the lines of:

245/45WR19 (front) and 275/40WR19 (rear)

From what I have found on Google searches, this would be a bad idea, because it would:
-throw the mileage off (but by much?)
-mess up the breaking system (don't know how, but many people claim this)
-make turning harder (not really sure how for this one either)

So what I wanted to ask you guys was, is this true?
Should I do this once I get the car? Or am I asking for trouble?
(probably have the car in 2 weeks to a month, but want to change tires and add an oil cooler as soon as I get it)

Any help would appreciated,
Thanks