Perhaps you can attend a show, not necessarily to scope out what to purchase, but to get a better idea of the kind of sound you hope to achieve. That would help in any effort to improve the speaker you have,or guide you in finding better cables, in use of room treatments, etc. There are no universally better parts; a change wrought by a particular choice might be going in the direction you want or it may go in the wrong direction. But first, you need to be clear about what direction you want to take. Cornwalls are lively sounding speakers whose vivid and exciting sound may come at the expense of sounding rough. Are you looking for an even livelier sound, or are you willing to trade off some liveliness or detail or some other quality for something else, like a warmer sound, or deeper bass, smoother (less edgy) sound or whatever. These tradeoffs and adjustments can be made with something as simple as adding or subtracting speaker stuffing, or changing internal wires, or changing crossover parts. It is NOT the case that technically superior parts (tighter tolerance, better electrical behavior) necessarily improves the sound. I know a builder who hunts down old, technically inferior resistors that others would say muddies the sound because they work in his designs and match the sound he is trying to achieve.
Regardless of what sound you are looking for, to me, the first modification of modern speakers to do is to add L-Pad controls to control driver output. Such controls are essential for tuning the speakers to your room, your system and your personal taste. It is madness to me that modern speakers builders think their chosen driver balance is ideal for all situations.
