Trex Search Results

We are implementing the B2C e-commerce solution in CRM v5.0 with a search function for products using Trex.

I have been unsuccessful finding the default sequence for the search results and would like to know where it is documented or if someone can explain it.

I would also like to know whether there is a method to alter the return sequence allowing the results to be displayed in a different sequence?

Does TREX prioritize search results based on proximity, relevance, popularity, pricing, etc, or can it be altered to use these characteristics to provide a result?