A car has to handle as well as it looks, and with the BMW E-Chassis cars, this runs true. Hopefully, no one is running on the initial stock OEM suspension since they would be beyond shot. Even though putting on a new set of OEM sports suspensions wouldn't be an issue since they rode pretty well once the run-flats were replaced with a performance set of tires. Below is a list of coilovers suited for the various types of drivers.
The Daily Driver - KW Variant 1
For a daily driver, comfort is critical. You want a ride that absorbs the bumps while allowing you to tackle those on ramps without compromising your trust in the car. We choose the KW V1 coilovers for this job. If you're located in a region that doesn't have winter and salted roads. You can opt for the ST V1's, which come out at a lower price. The only difference is that the ST uses galvanized steel, and the KW uses stainless steel.
The KW V1's are grand since they have strict quality control, uncompromising ride comfort, and performance at a reasonable price. The only thing to note is they don't come with bump or compression adjustment. But they are valved specific to the car, so those adjustments are on point. On our 335i on a set of KW V1's, they felt great, but if possible, id like about 2 more clicks of rebound adjustments. But all in all, a great coilover that handles daily driver duties while allowing for spirited driving.
The Fitment Driver - BC Racing BR
To lower your car while being static, meaning without using an air ride setup. You will need a coilover system with many adjustments and readily available replacement parts in the US. The BC Racing BR coilovers have camber plates, rebound adjustment, adjustable tierods, and readily available replacement parts. The price point is also quite competitive in which you can usually find them under 1k as of 03/22.
The very nature of trying to achieve any level of fitment will have you compromising ride comfort. Still, even while lower with about a few inches of clearance, the ride quality wasn't that bad. On a scale of 1 to 5, I'd rank it at a 3. These coilovers will get you real low while still offering decent ride quality. Again, with the nature of lowering cars, how long that comfort lasts is negligible, hence why readily available replacement parts are needed.
Daily Driver/Weekend Track Star - Bilstein B16 PSS10
Monday to Friday doing serious work, but you let off some steam and hit the track on the weekend. Nothing like having a dual-purpose car. For a dual-purpose car, you will need a dual-purpose suspension. Many great options for such a purpose, including the KW V3, but opted for the Bilstein B16 PSS10's. They are both comparable, and you can't go wrong with either. But the PSS10s have a softer ride than the KW's, which will be a blessing on those street roads.
These are suggestions from our experience running various coilovers on this platform. Hopefully, this will help you choose a coilover for your BMW E90 E92 E93.