Buying an E90 here are positives and problems to look out for.
BMW, 3 Series, 2009
How to Buy a Used BMW E90 3 Series
BMW 3 Series: The Ultimate Driving Machine Through the Years
2020 BMW 3-Series Review, Pricing, and Specs
The BMW E92 M3 Buyer's Guide
E90/E92 BMW M3 Buyers Guide
The Complete BMW 328i Buyers Guide
Performance BMW Magazine - February 14 Back Issue
BMW E90 3-Series Buyers' Guide (2022) — Everything You Need to Know –
BMW E90 3-Series Buyers' Guide (2022) — Everything You Need to Know –
BMW 3-series F30 330d/335d: review, specs and buying guide
BMW E90 3-Series Buyers' Guide (2022) — Everything You Need to Know –
Top Gear's guide to buying a used BMW 3 Series
BMW 3-Series Convertible (2007-2013) Buyers Guide