Quarter

Hi! I've just got myself a 2000 R50 with a few issues to address, so I'd appreciate any advice from you. As I hate driving with no music or a totally substandard sound, I looked at the stereo. There was some aftermarket 2din touchscreen station which produced harsh, scratchy sound with no bass whatsoever. Took it off and bought online a 1997 OEM Bose Clarion as I suspected I might have a Bose system (hence bad sound from the aftermarket unit that was hooked up without any Bose-nonBose harness). To my surprise, the plugs don't match (see the images). Does it mean that my Pathy has a non-Bose system? I don't want to dismantle the door trim to learn that by inspecting the speakers so your advice will be much appreciated. https://photos.app.goo.gl/TdJZ4ssc8TCohNYA9 https://photos.app.goo.gl/6kEefpZGqksWBs1WA https://photos.app.goo.gl/WQsw4MFKhTMB55ni9 Eventually, I hooked up a Pioneer unit - it sounds pretty bad, front speakers get overdrive and pop and give harsh sound, the back speakers are slightly better but overall it's bad. I'd rather have an OEM (I like the looks of the 90s/00s units but can live with aftermarket stuff as long as it sounds passable. Would like to avoid installing new speakers and all new wiring if possible. Thanks in advance for any thoughts. PS. I'm based in Poland so, unfortunately, I cannot order anything from Crutchfield (they don't do intl. deliveries) which seems to be the go-to place for stereo issues. PS.2 I'll say "hello" in the newbie section soon, I know the drill