This product from procarparts is fairly priced, however you would only get the apperance of the e39 headlights. When these procarpart lights are turned on, it'll be a different story. The optics would be different as these halogen projectors are not intended for a xenon kit. To make full use of the e39 conversion, I'd recommend going with a true xenon projector and system. Also, these aftermarket lights would only come with a rather yellow/dim halos that wouldn't be comparable to the originals of the BMW. I would think that when the headlights are on, it'll drown out the halos.
It all boils down to your budget. If you are going to spend some $ doing a custom fabrication to your car, I would spend on a quality set of headlights. I'd recommend going with some OEM parts or a quality aftermarket parts that includes true xenon projectors, xenon system, and (daylight demon eyes) DDE tranformer+rings that would light up bright. The DDE systems are much brighter than stock (which are also brighter than the aftermarket @ procarparts). Just an FYI, the optic colors, ring effect, and cut off beam of these "affordable" procarpart lights would not be the same as oem's. Hope this helps.