Suzhou: "Biluochun" is about dried tofu and yellow Tianyuan cakes.
Wuxi: ribs with Sanfengqiao sauce (this brand must be used), Yangshan peaches (authentic ones should be bought locally in Yangshan), Huishan clay figurines (there are many shops near Xi Hui Park), Yixing teapot, etc. (PS: I am from Wuxi).
Shanghai: City God Temple spiced beans and pear candy (PS: Grandma is from Shanghai).