Hello guys, I currently have Opel Astra 3 door car, which is pretty small car, and wanted to upgrade the audio system, bought a good Sony CD player with bluetooth, and those speakers - Hertz DSK 170.3& Hertz CX 165, they are rated from 80W to almost 200, they have different Watt ratios so my question is what amplifier to chose, because I want to put the more powerful one in the back and have them working properly. My CD currently outputs 4 channels on 50W, I am thinking also on buying a sub if the bass is not enough with those speakers, but I think that I wont need one, because they are pretty powerful for that small car, any mid tier amplifier recommendations will be very helpful, thank you