What evidence is there for China wanting to expand? It seems like they have made claims to disputed territories based on historical claims. They have a claim on Taiwan and and some disputed islands, all which had been under Chinese control in sometime in the past. That's not imperialism or colonialism. Look at Japan's behavior early 20th century. They took Korea, large parts of China and south pacific islands, things they never had a claim to and that is imperialism. Even Tibet had been under Chinese rule throughout centuries of history.
It seems like to me that China is only interested in achieving the same kind of cultural dominance and influence they've had through history. I've never read anything about China wanting to expand territory outside of traditional China.