The Paul Bracq designed E12 luxury sedan was the first BMW to wear the 5-series name. It was a huge leap forward in performance and build quality when compared to the E3 (aka Bavaria) it replaced, but isn't quite as well built as the E28. Fortunately prices for a nice E12 are very favorable for the buyer and nice ones are cheap. Find this 1981 BMW 528i here on eBay offered for $4,850 buy-it-now located in Washington, CT.
This E12 528i is powered by a 2.8 liter M30 inline-6 rated at 169 horsepower and 170 ft-lbs of torque for the USA market. While criticized for US spec bumpers and sealed-beam headlights, most sold on this side of the Atlantic were equipped with supple leather, and loaded with creature comfort options.
This one looks as nice on the inside as it does on the out (with the exception of some rusting in the interior door panels, trunk lid, a side marker lights.) However, for the price it seems like it could be worth a look.
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