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.
The complexity of speaker design is an arcane art.
Books like Loudspeaker design cookbook can be a start.
Each driver has it's own parameters. that match up with different enclosure volumes and crossover etc.
The "Thiel small parameters" can make your head spin!!!
So it is way more than just putting a better driver in an old cabinet!
If you really want a good quality speaker for less, I would try the kit companies like Madisound for a complete kit. Then at least you will be putting together stuff that is designed to work together.
Good luck.
Klipsch mods can be found here-
Everything Elizabeth said. Also though, a call to madisound might be worthwhile. Sometimes there are drivers that come close to exact replacements, and those guys can be a big help. Vifa makes a very wide range of drivers and is moderately priced. Scan Speak is not inexpensive, but performance is probably worth the investment. Just in case you can build boxes though, build something. My first venture in building was a bookshelf with a Scan Speak midwoofer and tweeter, and simple crossover. That little speaker blew my ADS L980's in the weeds and I sold them soon after. I took the little speaker to a local shop, and we compared it to every bookshelf speaker in the store. It took a floor standing Kef to beat the sound of the little bookshelf Scanspeak. Sorry to ramble, but you sound like you might be a future speaker builder.....there is software, BTW, that helps to solve all that Thiel stuff, and designs crossovers. I use Bassbox. Anyway, I think you will have success with your project. Just my opinion....paper and carbon fiber impregnated paper cones make for sweet midrange.