Forgive me for having no idea, but using speakers rated as 4 or 6 ohm, what do you have to look for when buying a suitable receiver? Specifically im looking at the azur 640r which is rated as 80w x 6 at 8 ohms, and 100w x 2 at 8 ohms. So what effect would using 4 or 6 ohm speakers have? Would it be ok or do I need to look elsewhere? Cheers.