The 140/160 series used wheels with 40 mm offset. That's why fwd and late 960/90 (43 mm) wheels are the closest match. I've used 960 6.5x16x43 wheels without problems but they are very tight on the front inside because these cars were designed for no more than 5.5' wide rims. Wider/bigger 43 mm wheels might work but 200/700/900 wheels with 20 mm offset, such as the Polaris, provide a simple choice since they won't interfere. The 140/160 suspension is relatively insensitive to offset changes - most people say the decreased offset doesn't do any harm in terms of handling and ride. I haven't tried, though.

Martin
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'65 121, '73 165