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Non-racing commercial activities

In the late 1980s, to take advantage of the relationship Honda had formed with Senna, the Japanese company asked him to help fine-tune the Honda NSX 's suspension setting during its final development stages. Test runs were conducted at various circuits, including five sessions with prototypes at the Suzuka Circuit where chief NSX engineer Shigeru Uehara and his team were present to gather Senna's direct input. Senna found the prototype NSX initially lacked chassis stiffness to the level to which he was accustomed, so the final production version was further reinforced to his satisfaction.

Senna reportedly had access to three of these cars: a black 1993 NSX in Brazil, which he ordered to his specifications, bearing license plate BSS-8888, which represents his initials for "Beco" – his childhood nickname – "Senna da Silva" and 8 to commemorate his first Formula One World Championship in 1988; a red one with licence plate SX-25-59, which was loaned to him by Honda Portugal; a black one purchased by Antonio Carlos de Almeida Braga, who was a close personal friend, manager, and mentor of Senna.

Senna appeared in different commercials for the 4th generation Honda Prelude, and was instrumental in bringing Audi cars into his native country, both as an import and manufacturing business. Audi entered Brazil in 1994 via Senna's company, Senna Import, founded in 1993. Sales began in April that year, just a month before his untimely death. In 1999, Audi Senna was created as a joint venture of Audi with Senna Import. Aside from the black NSX mentioned above, Senna's other personal car in 1994 was a silver Audi 100 S4 Avant.

In the early 1990s, Senna developed his own merchandise brand represented by a logo with a double S, after his full surname, "Senna da Silva". This logo is meant to represent an S chicane on a racing circuit. The Senna brand was used for apparel, watches, bicycles (Carraro), motorcycles and boats. Hublot, TAG Heuer, and Universal Genève have created limited-edition watches to honour Senna, both during his lifetime and after his death.