In the following sentence, the use of "which" instead of "that" creates a logical fallacy:

"I looked at two shipping models--the Jaw and the Maw--which could save your data."

The sentence implies that the writer's very act of looking could save your data. Seems unlikely. Remember: 1) A "which" clause goes inside commas; and 2) if you can lose the clause without losing the meaning of the sentence, the word you want is "that." The phrase between dashes confuses the issue. If you cover it up, you can see that "which" refers to the act of looking. We can be sure that wasn't the writer's intention.

Here are a couple of solutions:

"I looked at two shipping models that could save your data--the Jaw and the Maw."
"I looked at two shipping models, the Jaw and the Maw, either of which could save your data."