As a long time LS5 II and III owner, who praised these models on here 20+ years ago, I would be hesitant to put a lot of money into this. If it sounds good to you, then just run with it. But if you're looking to put $1k into this, I would suggest you consider alternatives.
My line stage progress since then: ARC LS5 III --> BAT 31SE --> Aesthetix Callisto Sig --> Aria WV5XL which I have had for 15 years. Each change was a significant step up with the last two being VERY significant refinements.
After you hear these models and many others from Cary, Canary, VAC, it's hard to go back to the LS5 as it is just too unnaturally forward sounding and lacks the energy in the low end. About 10 years ago I got an old Counterpoint SA-5 for a small apt system. At that same time, a friend got a used LS5 II as he found a good deal and he knew of my praise of it years ago. We ran them side by side and the LS5 lost to the SA5 in a flash. Even his wife in another room asked what we did right when we switched to the SA-5. He sold the LS5 and got an SA-5 and put money back into his pocket. I am not pushing the SA-5, and surely you can do a lot better, but I am pointing out that there is so much out there so be careful what you spend on updates.
As for capacitors, here is a cool read: Capacitor Review Test
John