E60 Wheel upgrade/non run flats

[finmac]

Toying with buying a 530D at the mo and will likely upgrade to 19" rims.

So three questions:

1. What tyre/rim size to go for
2. What about the tyre pressure sensors when the run flats are removed, does it stay illuminated all the time?
3. Any suggestions as to where I could buy a set of M5 "style" rims?

cheers