BMW suspension upgrade guide - coilovers vs lowering springs vs air suspension

Great guide. I'd add that for E9x owners specifically, the M3 control arms (or aftermarket adjustable ones) are almost mandatory with coilovers. The stock non-M control arms don't have enough camber adjustment to properly align the car when lowered.

Also, don't forget about sway bars. A thicker rear sway bar transforms the handling of any 3 series. H&R 26mm rear on my E90 was the best 200 EUR I ever spent.

Running Ohlins Road & Track on my E92 M3 track car. They're expensive but worth every cent if you do track days. The damping is incredibly well controlled and you can adjust compression and rebound separately.

For pure street use though, I agree KW V2 is the sweet spot. Ohlins are overkill for daily driving.

I went with H&R lowering springs on my G20 320d and honestly for a daily driver it's perfect. 25mm drop, looks great, and the ride is only slightly firmer than stock. Cost me 280 EUR plus alignment.

Coilovers would have been nice but I couldn't justify 1500+ EUR on a daily that never sees a track.

One thing people overlook - if your car has adaptive suspension (EDC), lowering springs or coilovers will disable the adaptive function unless you get a kit specifically designed for EDC cars. KW DDC and Bilstein B16 DampTronic are the main options that keep EDC working.

Also, for F and G series cars with lift-related dampers, you need coilovers that account for this design. Standard coilovers won't work properly.