The turbo spedo will have the black center cap on the needle. I think the 240 uses the silver cap. some times the caps will come off easy. I have had a few fall off, think the glue has got old and lost it grip. or you can swap the needles.
before you pop the needle off. lift it over the resting peg, and see where it rests. should be a little white mark on the edge of the face. needle should line up with that spot. replace the needle in the same place, then lift it back over the peg. i had to redo my 85 a couple times to get it to read right.
you mention you want the spedo to look correct (85 mph). I have a 150mph in my 240D

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Charlie