The Bilstein 22-139948 is a front right strut assembly sized for the BMW E46 3 Series, the passenger-side unit in US-market cars. Owners on user forums report fitting the Bilstein B4 strut to an E46, so the B4 line is an established choice for this chassis. Fitment details vary across sources, and the 2001 320i in the product title is not confirmed on the data we reviewed, so check the trim against your VIN before ordering. A matched pair is the cleaner way to restore an even ride, and replacing both fronts together keeps the left and right corners behaving alike. Search terms: E46 front strut replacement, Bilstein B4 E46, BMW E46 right front strut, 22-139948, E46 strut spring compressor.
Installing one of these is a moderate job rather than a bolt-on. Owners on user forums describe the fronts as harder than the rears, but doable, and the main obstacle is compressing the coil spring to fit the top mount. A spring compressor is needed, since the job is difficult without one. Wheel alignment is a must once the struts are back on the car.
Owners on user forums note that most people disconnect the outer ball joint from the control arm to get the spring compressed. Other owners report that the ball joint does not need to come apart, so the approach varies by setup.
Owners on user forums consider alignment essential after a front strut replacement. Wheel alignment is a must once the work is complete.
Plan on a spring compressor, a torque wrench, and a helper to hold the knuckle. Align the spring on its seats correctly, doing one side at a time and copying the original. The strut housing often has a small nub that slides down a slot in the steering knuckle, and a groove in the strut has to line up with the pinch bolt. One owner reported finishing both fronts in about three hours, but they had to rely on an improvised strap around the spring, so a proper compressor is the safer route. Get the wheel alignment checked afterward.
