Hey guys...I
I have a 98 es, with the regular stock speakers...Can i upgrade or get Mbquarts speakers, in there with an alpine sub? Would I need a better amp? Honestly, I dont know what an amp does, but do i need a better amp? I really wanna keep my stock head unit, and I really just want something thats not gonna show off, but ready to poung when i want it too

Is it true that if I upgrade the amp, I have to upgrade the head unit or buy another one????
Thanks....