BIG difference, much clearer sound and the highs are higher and lows are lower. I wish I had the intestinal fortitude to take a router to the bottom of the cabinet and bore out the hole to the size of the sub because I'm sure it would sound even better..
One question - I don't believe the Pros had the crossover that the Premiums and LE's had. Can you upfit a Pro with the crossover and make the sound better from the factory speakers? If so, I have one I am not using