Also, became a much richer region, because after the centralization got access to world-wide trade because of the Spanish Empire.

And with that definition/benefit you've stated, how is that different to colonialism?

Catalans were doing colonialism within the Spanish Empire. I.e. doing the colonialism, not suffering it.

Getting rich as in- getting flooded with indio mined cheap silver, driving inflation of the currency ever onwards, while mercantilism ruins the competition ability of ones industry?

Out of curiosity, how do the Catalan constitutions Charles promised to uphold compare to the current autonomy?

Also, is it historically accepted that, if Charles had won, he wouldn't have done the same to the other regions with fueros / constitutions?

The Crown of Aragon, which controlled the territories of modern-day Catalonia, was an independent state in all ways aside from military and foreign policy. The union of Castile and Aragon was a dynastic union, with very few shared institutions until the Kingdom of Spain was established in 1716. Aragon itself was a fairly decentralized state with constituent principalities having their own Corts and legal systems (rights referred to as "Furs" or "Fueros")

> was an independent state in all ways aside from military and foreign policy

It was still an absolute monarchy with the same monarch; it's not like the Aragonese were free to choose their own destiny. Still, the Constitutions Charles promised them to uphold must have given them something, I just don't know what it was. That's why I'd like to know how they compare to the current rights granted by the autonomía.

Most European monarchies were not absolute. The nobles, the burghers and the church could of often have substantial powers. A king ruling a bunch of regions with varying degrees of autonomy was the norm.

The King of the Corona was far from an absolute monarchy, and there limits to what the monarchy could do. The Fueros were a kind of primitive Constitution pacted between the king and the kingdom (mostly the nobility), and nobody was above it.

Of course this put severe conatrains to the royal power, and the Habsburg had been trying for a long time to get rid of the Fueros and it was the first thing the Borbons did when they took over the Corona.

What were these limits? What did the Constitutions allow the nobility do against the will of the king, assuming a king that wanted to uphold them?

> nobody was above it.

It's not like there was an independent judiciary branch with the power to enforce that against the nobles or the king. Case in point: the king decided to eliminate them and he just went and did it.

It was not an absolute monarchy, that's the point. There was a balance of power between the king, the church and the nobility. A comparison with the current statute autonomy seems difficult since it was an entirely different form of government.