Replacing The Quad ESL Capacitor

Hi
I spoke with my friend, a certified Quad technician and got onto the topic of upgrades. He told me that by replacing the .30 cent, 220 Micro Ferrite Capacitor with a higher grade/higher cost capacitor could potentially improve the sound of my 2905's. I am not experienced in making repairs, etc... but I was told that I could do this on my own. The biggest problem that I'm having with getting started is knowing which parts to order. I've looked around at other discussions but it's still not clear to me.
Initially I thought about posting this topic to the tech forum but this speaker forum appears to get more traffic. Any related help here would surely be welcome.
Thanks!