Depends on how loud you want everything to go. Are you planning on being able to hear in the next 3 years or going deaf? If you're just going for decent sound quality, not huge volume you should be ok. I used to crank mine pretty well with only 2 5.25" three ways and 12" sealed box Pioneer. Since moving the 6.5's it can ring my ears and still sound clear and crisp from inside the car.

 

ok thanx