I hate to alter the current exchange on movie version of PS. Everyone appears to be having a hay day about casting.
I ran into this scholarly article (published in 1998) that provides insightful commentary on Chola trade with Indonesia. Although we have only scant inscriptional evidence, the motive for going to far flung land is worthy of research and contemplation. In any case, you thoughts and comments would enrich the conversation on the Cholas.
The article has free access; if you have trouble accessing it, I would gladly send it by email. Since it is copyrighted material, posting here may be inappropriate.