The crossovers are original. I have verified all the components as the same except the caps. I have also verified through millersound and others on this site there were mods by infinity to the crossover caps.
The speakers were built in 1991 and the caps are dated the same. Makes them about 26 years old. I want to replace them because of the big improvement I got when I replaced the kappa 7 caps. I believe those speakers were built about 1988 so those caps would have been about 3 years older.
I will be sure to save the old ones just in case I don't like what I hear. By the way they do sound fantastic now that I have sorted out the positioning.
Just because you put better caps in them doesn't mean it will sound better, infinity has an anechoic testing chamber, computer design, special testing equipment, noise generators, professional speaker engineers/designers that also do the final tweaking of the speaker by ear.
Infinity spent countless hours and money choosing the right caps that enhanced the drivers sound qualities so that the speaker would have good timber be coherent and measure flat.
There is absolutely no way the average guy or even a guy with an electronics background can slip in new caps and claim the speaker sounds better than what infinity did because you don't have the tools or anechoic room that infinity had to measure/test it.
in stock form you hear the speaker as a whole, drivers blending together smoothly, once you switch the caps you will start to notice the individual drivers sticking out making their own sound because they're not blending together smoothly anymore.
Switching caps is tricky because they all sound different for better and for worse, just because a cap is more expensive doesn't guarantee it will sound better for the application, some caps are louder than others and the list goes on.
You might get a tad more detail because the caps are better quality but that's about it.