According to my estimation, per capita GDP (PPP) in Shanghai will match the level of Taiwan. But this simple average does not address the issue of the gap between urban and rural areas, the distribution of wealth, and other structural issue of economics. Besides, the definition of municipality is more like something in between a metropolitan or a region. Comparing Shanghai with the whole Taiwan may seem inappropriate. The area of Shanghai is approximately equal to ¾ of Hsinchu County and City, Yilan, and everything north of them, or Delaware.
When I was collecting data, I found this article, which states that China (didn't specify whether it's mainland China or the whole China), in between 2025 and 2030, will reach the level of Korea in 1991 or 1992, and becomes a developed country in between 2055 and 2065. The blog has many interesting posts. I added it to the links on the right column.