You would probably feel more with a sub. How much that's worth to you I don't know. I bought a used SVS sub cs20-39 for under $300, and they are frequently for sale by people upgrading to the latest and greatest.

If I had mains that went down to 30hz, I would probably turn the sub off for music and use it only for HT. You would get much more coherent sound that way, and most music doesn't go that low.