Trying to learn about speaker design and mods

I have always wanted to delve into the higher end of speakers but my budget doesn't lend itself to that quest. I see mods available for so many cd/dvd players and receivers where cheaper components are swapped out for better quality components in an attempt to keep the digital signal as perfect as possible. Does this hold true for speakers as well? For instance lets say I have a pair of the old Klipsch Rp-5's which consisted of the tactrix horn, mid-wooofer, and 12" subwoofer with a built in amplifier. The midwoofer is composed of that polypropolene? material that looks like copper but isn't. The highs with this speaker but the mids have always been described as muddy. Hypothetically if I pulled the standard midrange out and replaced it with a titanium midrange of much higher quality but the same 8 ohm capability would it work? I have tried to understand all this Q and thiel stuff but I work in medicine not electronics. I would appreciate any advice I can get. I had this crazy thought that by replacing the mids and subs in these speakers I could end up with a cleaner more accurate sound without having to save thousands of dollars to buy new high-end speakers.