Glad to hear you are on the right track! Hopefully the crossover rebuild will take away the muddy bass. The Ti tweeter will help smooth things out as well. Keep in mind Klipsch speakers overall are probably the most revealing simply by design. Garbage in, garbage out, from a recording perspective. Poorly mastered CD's etc. will really shine with all their glory through all Heritage designs.
The forte line is considered among the best in the Heritage line in the sense of a well balanced speaker. Cornwall I-III, will have less midrange, but a more robust bass. LaScala, great mid and highs, but lacks bass. Think 1-2 subs in the mix with that route. I have owned my forte II since I unboxed them 28 years ago. The only Heritage that has come out since then that I would replace with is the new Cornwall IV. However they are $6K a pair. Will wait a couple years till they are available on used market for half or less. The new Cornwall IV INMHO is like a forte III on steroids. Finally gave it the larger mid range it needed for decades. INMHO, they stole Bob Crite's 3 way Cornscala design, more or less. Lol.....
Remember as PWK stated we live in the mid-range.