Have you see those caps that go over unused RCA jacks?
There supposed to reduce interference. At $50 for a set of 8. Seems like a silver-plated RCA dust cover to me. If it works then that's different.

Crossover upgrades are the best. I actually like doing this.
It makes a huge difference if the original components are low quality.





M80's VP150 QS8's Earthquake SuperNova MKV-15
Integra DTR-7.4 Outlaw 755 Outlaw M200's Outlaw ICBM