they're going into a 2003 mustang. the size is either 5x7 or 6x8 i dont think it matters. They will be powered by a 35 watt amp x 4 and a 18 watt deck so will i need speakers that need around 50 watts rms? i don't know if thats how it works I don't know a lot about it. but i was looking for components up front and just coaxials in the back looking to spend hopefully around 200 bucks maybe less.