I also heard a rumour that the opening Chinese display will have over 8000 pieces ...
More than relatively large - it would be the largest ever, the previous record holder firing around 7700 pieces if I recall correctly.
Grupo Luso Pirotécnia did a huge display in 2008. At time, I reported on PyroPlanet that the show was made of about 8000 pieces. I believe this information was from Paul Csukassy, who also told me that he was not sure whether this show was the largest, or "only" one of the largest. Below is a segment of my PyroPlanet report:
According to Paul Csukassy, technical director of the competition, Grupo Luso Pirotecnia brought the largest number of aerial shells ever fired within the framework of the Montreal International Firework Competition. "There were about 5000 aerial shells. We had to find more than 800 3-inches- and 4-inches mortars, because our 2600 mortar for that size of shells were not enough", said Csukassy. The show had around 8000 pieces, less than the American show performed by Pyro Spectaculars by Souza in 2001, according to La Ronde's officials. However, the press release of 2001 about this display stated that it was going to be made of 7738 pieces. At the end of the day, it remains unclear if the Portuguese show was actually the largest, but it was obviously one of the biggest produced at La Ronde.
http://www.pyroplanet.com/article487.html
Fred