I think as long as they are a high quality brand that is the proper fitment, it won't void anything. The only time I could that happening is if you wanted to throw some negative off-set, deep-dish Daytons on it, and you ended up screwing up a lot of suspension components.
You don't have to use run-flats, however I would do some investigating on how you car will handle with regular tires. I've heard that the suspension setup only works optimally with run-flats, but I would check for myself.
There is an entire Q&A section at tirerack.com that explains all the detail of rims including: offset, proper fitment, lug nuts, hub-centric, etc...
http://www.tirerack.com/wheels/tech/offset.jsp