80 watts RMS. Having pioneer say that they handle 420watts peak just made me mildly throwup.
Any decent 2 channel amp, somewhere around 50-100 watts per channel will work fine. for amp selection threads, there are about 1000.
What type of car are you putting this in? I take it you are putting the 6x9s in the rear of the car? Whats in the front? When you go to a concert, do you face towards the back of the stadium? When you watch TV, do you turn around an look at the back wall? no... no you usually FACE the speakers that are presenting the majority of information. So why put your best speakers behind you?
Get a set of great speakers for the front of your vehicle. Look into decent coaxials or component sets. Many people, including me, run only front speakers. If these 6x9s are for the front doors (pick up truck) then i highly recommend making a plate and installing 6.5" components instead.