The RCA outputs should be line level, and a good amplifier would be a big help in achieving clearer, louder sound, with any speakers, but.... If you didn't like their sound before, you won't after adding an amp. Also systems work better if the components are matched, and thus, it would be better to buy amplifier and speakers that are well matched. BTW, "distort" is the verb form, and "distortion" is the noun version in English. I'm ashamed to admit that I had to reference how to spell Portuguese, so you're way ahead of me in linguistic abilities.
