I dont think that you will have any chance of the Hella lenses fitting the Bosch lamp units, I replaced the Bosch units on my Evo1 with RHD Hella units and the design of the lense clips right through to the adjustment unit was totally different. I cant say that the Hella quality was up to much either but seen as MB only choose Hella to manufacture the 500E/E500 headlight there is not much choice. The other advantage of the 500E unit is that the lense internal plastic section is chrome rather then the dull silver of the normal 124 type.If I pluck up enough courage to buy at £160GBP each I will let you know. Regards Linds