The H&R 50490-5 is a progressive-rate sport spring set for the E93 3 Series convertible, made from 54SiCr6 spring steel at H&R's German plant. It replaces the factory front and rear coils to lower the car and firm up its handling without the jolt of a coilover setup. Compared with stock, it lowers the car's center of gravity, reduces body roll in corners, and closes the fender gap for a more aggressive stance, while the progressive rate keeps daily ride quality usable.
Choose this kit for a 325Ci, 328i/Ci, 330Ci, or 335i/Ci convertible if you want a sharper street setup at a lower cost than a coilover system. Owners on user forums say the springs handle well on the street and on occasional track days, but they also stress that shocks should be upgraded at the same time, since stock dampers are not matched to a lowered ride. Search terms this part matches include E93 convertible lowering springs, 335i convertible sport springs, and N54 progressive rate springs. Fitment is the first thing to check: model-year ranges differ between sources, so confirm your VIN against the application before ordering.
No. The manufacturer's separate M3 convertible sport spring kit uses a different part number (29053-2) and lowers approximately 1.0 inch in front and 0.6 inch in the rear, so it is not interchangeable with 50490-5.
Owners on user forums consistently recommend replacing the shocks or struts along with the springs, because stock dampers are not designed for a lowered ride height and tend to wear out faster with lowered springs.
Yes. Vehicles already equipped with a factory sport or M-Technik suspension may lower by a different amount than the approximate figures listed, so measure your fender gaps before and after installation.
This is a moderately difficult DIY job, and owners on user forums describe the front struts as the harder side. You will need a quality spring compressor, jack stands, a torque wrench, and a set of metric sockets, including 17mm, 19mm, and 21mm sizes. Owners report that the front strut-to-fender nuts and the rear control arm bolts take the most time, and the rear inboard bolt can be tricky to start during reassembly. Mark the rear bolt head and washer before removal so the offset flange lines up again. Some owners also need to loosen exhaust hangers to clear the rear control arm bolt. Budget extra time, and plan for a wheel alignment after the springs are in.
