Bmw e36 Sound Upgrade

I just recently bought a bmw e36 328 coupe. I want to upgrade the sound! I'm mainly looking towards sound quality. I've decided on the rainbow slc 230.25 ng and later adding a mid range ( not sure what mid range though) I don't really want to do any modifications to make speakers fit. I just want to take the old out and put the new in replacement. I'm not sure what amp to buy for these components and since I most likely would add a mid range I don't wanna have to CHNAGE or buy another amp later on. Also I'm not sure what headunit I want. I've heard good things about the clarion cz702 but according to crutch field it won't fit my bmw ( I think it's just confused )


All suggestions welcome!

thank you for your time!