This is going to require a hands-on inspection. Looks like you've replaced a lot and it's time for a full diagnosis.
Use this link to find a good shop near you.
https://repairpal.com/repair-shops
Alex
RepairPal Certified shops can diagnose and repair your 2000 BMW 323i. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.