I drive a 123, and a 126 routinely.
The 126 (SD) has a superior ride, inferior interior. It's bigger, and heavier, which explains part of it.
The 123 (CD) is more responsive, quicker, (different rear end gear, too) but that can be any number of things. Nimbler, too.
"Beauty is in the eye of the beholder".

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83 SD

84 CD