I just put a blaupunkt (san diego) head unit in my 81 240D, 5.25" infiniti speakers in the back deck and 4" infiniti's in the dash. All was shipped to my door from Crutchfield for about $200.

I had to do some minor modifying to the 4" speakers....the speakers have this huge plastic thing covering the tweeter up and I just took it off (I wanted it to fit under the orignal grill). The deck speakers fit just fine...but I still. need to pick up a larger grill cover. I did run all new speaker wire and I bypassed the center fader.

Obviously, powering with an amp would be preferable and you can spend much, much more for better equipment. But for me? It works just fine on my limited budget.

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1981 240d - 135k - Arlene