Partscheap.com (for OEM pieces if you don't have an SEL trim), eBay, and steedafusion.com. The latter is a little pricey, but excellent in quality.
That's about it really, most of the visual customizing I've done has been from eBay.
turbostroke, you said you had 225/45/18 tires on the Edge wheels, when the tires that come stock on those wheels (on the Edge) are 245/60/18.
How did the 225 tires fit on the 245 rims, did that extra 2cm make a difference?