For tours of parmesan cheese producers, we went with Claudio and enjoyed it tremendously (did the balsmaic tour in the afternoon) Small group; he picked us up, took us to the cheese producer, then on to see the cows, and then to a farm for a cheese and wine tasting. We also joined his afternoon tour of a balsamic producer. Claudio is charming and fun and was great with my teenagers. My boys still say it was the best thing we did during the whole trip!
https://www.airbnb.com/experiences/91363
We didn't do this tour, but this group gets very good reviews on this site: https://www.italiandays.it/
In terms of Bologna food tours, we went with Mattia from Delicious Bologna. Comprehensive and hit all the highlights of foods and key neighborhoods.
https://deliciousbologna.com/about/
This tour company also gets good reviews (she was featured in one of the Somebody Feed Phil episodes)
https://www.tastebologna.net/
Bologna also has wonderful gelato. We went to Cremeria La Vecchia Stalla and Cremeria Mascarella. And don't miss the famous Fiat chocolates at Majani!
For cars, we went to see the Pagani factory, where the cars are handmade and the factory floor is cleaner than a hospital room.