And if I remember correctly he changed the spelling because the numerology worked out better
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Yes, this is one of the reasons cited.
Hopefully, Yoshie will correct me if I'm wrong but I believe 8 strokes are needed to write "Toyota" in Katakana. The number 8 has traditionally been considered lucky in Japan.
Numbers aside, Kiichiro also wanted to create brand differentiation from the well known Toyoda Textiles name. Not unlike Audi/Volkswagen (which were once quite different but are now almost identical) or Toyota's late 20th century creation of the Lexus luxury division.
.d.