The H&R 50490-4 is a four-spring Sport Spring set for the 2007–2011 BMW 335i Sedan (E90). The manufacturer says every H&R spring is made from 54SiCr6 spring steel at its ISO 9001 certified facility in Germany, with each spring tested before it ships. Sport Springs are H&R's best-selling product, and they are meant to lower the center of gravity and reduce body roll while keeping the ride comfortable enough for daily driving.
Compared with the factory setup, these springs add firmer control and a tighter stance, and they fill the fender gap. The manufacturer states that its springs are shot-peened for longer life and will not set or sag, which matters on a car that sees hard cornering or occasional track days. Owners on user forums say the ride is firmer than stock but not harsh, and that the car feels more controlled than with the OE sport package spring. Compared with cheaper no-name lowering springs, the value here is the steel, the shot-peening, and the documented German quality control. Drop amount varies from car to car, and owners on user forums report that results depend on whether the car originally had factory sport suspension.
Fitment is for the N54 and N55 3.0L inline-six in E90 335i sedans. Stock dampers can be reused, but many enthusiasts pair these springs with upgraded shocks, especially for track use. Installation is a practical weekend job with a set of spring compressors, jack stands, and basic hand tools, and it is best done as a complete strut and spring refresh.
Fitment is listed for the E90 335i Sedan. Sources do not agree on whether all-wheel-drive xDrive models are covered, so confirm your chassis and drivetrain with the manufacturer before ordering.
Owners on user forums report running these springs with the factory dampers without problems, while others say that upgraded shocks give a better ride and control, particularly when the car is lowered further or driven on track. The manufacturer does not give a single required shock setup, so the choice depends on your goals.
Owners on user forums describe the job as straightforward for anyone with prior spring experience, though a first-timer may need five to six hours. Plan on spring compressors, jack stands, and a set of sockets that includes 19mm, 21mm, and 10mm sizes. At the rear, the outboard control arm bolt is removed, and it helps to mark the washer and bolt head with a marker so the offset flange goes back in the same orientation. At the front, some owners remove the complete strut assembly rather than compressing the spring on the car, which avoids scratching the fender. Replace the springs on both sides together, and check that the rubber spring seats are seated correctly on each spring.
