I pulled out 19A Automaker that went bankrupt in 2011: SAAB because I had liked that brand when I was a child and thought I’d get one and knock off the S from the badge and replace it with an R. But then I started learning about cars and didn’t think I’d ever get a Saab, and then they went under, and that was that. Also Saab is pronounced Sob, while Raab is pronounced Rab.

Theme!

20A What intellectual rivals engage in: ABATTLEOFWITS -> (A)BATTLEOFW(I)(T)(S).
37A “Theodore Roosevelt” or “Robert Louis Stevenson”: SARGENTPORTRAIT -> (S)(A)RGENTPORTRA(I)(T).
58A Mid-19th-century Russian ruler described as “autocracy personified”: TSARNICHOLASI -> (T)(S)(A)RNICHOLAS(I).

68A With 66-Across, director’s cry … or hint to 20-, 37- and 58-Across: ITSA WRAP. Because ITSA wraps around the grid with each clue.

Finished this one in 12:10.