Help me please someone!!!!?

I got two fli subwoofer speakers a 1000 watts each, my amp is a phonics 2000 watts digital amp, I don't know much about car systems but I heard phonics is not great, so I was wondering if I can just buy a different brand amp like autotek or something better, will that improve my sound system by just changing the amp and not the speakers? or do I have to buy different subwoofers too? I really appreciate you're Reponses thank you