Q: will 19's rub on the archs when in full lock?
A: Yes they will rub... and 19" alloys will need an expensive suspension upgrade as well (because the low profile tyre will have very little cushioning effect). The only way you could fit them (and still go around corners) is to fit hydraulics where you could raise the car high enough to turn the wheels, then lower it when parked. I have seen this on a Jaguar XJ8 which had 22" alloys.