Selling or repairing

Hi, data about the vehicle: Mazda 3 BK 1.6 Gasoline Active 2007 air conditioning automatic parking aid retrofitted defective beeps almost always 117000km running power 3 previous owners For about 3 years I have probably had sides damage allegedly from the bike Has been partially made. Technology is so good. If I read here what can go wrong. All this has my not but brakes+ liquid needs new oil tank leaks free workshop wants 100€ working costs clutch pedal at motor from and also on qwitscht but is still good total ca 800€ incl. clutch if not even more outside scratched and various damages lackaplatzer bumper loose Hard rust except small points stone blows residual value ca. 220€ by we buy your car probably on site few hundred euros comparable ca 3300€ by dealers who are probably better from the optics and they get even new tüv What do you say what I should do with it? Lg Hans