If these were single-xenons, I'd say your projectors are probably worn out, i. e. after years of use, the mirror silvering inside the projector has burned off. Are you sure they're *bi-xenons* vs. single xenons?
Are the W203's similar to the W211's (the E class) in that the inner light on each side is the high-beam light? If so, then even if you do have bi-xenons, the mirroring could be worn out. This very thing happened on my S600 with bi-xenons; they were so dim that I considered the car unsafe to drive at night until I could rebuild the headlight assembly with new projectors. This is not difficult at all to do on either W211's or W220's, and having watched videos of people doing it on W203's, it looks like essentially the same process.
Are the W203's similar to the W211's (the E class) in that the inner light on each side is the high-beam light? If so, then even if you do have bi-xenons, the mirroring could be worn out. This very thing happened on my S600 with bi-xenons; they were so dim that I considered the car unsafe to drive at night until I could rebuild the headlight assembly with new projectors. This is not difficult at all to do on either W211's or W220's, and having watched videos of people doing it on W203's, it looks like essentially the same process.
