I bought the TVT tubes, but opted NOT to get the devils horns. For $110, I'll pass. My father said the same thing about those horns... that they're a huge waste of money. I argued with him for about an hour until I was convinced that he had a valid point. There were two things I argued. I said that by getting the horns lined up behind the open grill you A) get colder air and B) get the advantage of the air pressing into the tube better. He said the difference was so negligible that he wouldn't even pay $10 for them.

Just saying what I ended up doing.