Yes, definitely. Miflex KPCU is even better, but larger and costs more. Bypass them with high-end 0.1uF caps -- lots of options available.
Thankfully, they come in 250V versions, which tend to be a little smaller/cheaper than the standard 600V options.
The Jantzen caps will likely be more of a side-grade rather than an upgrade to Somicaps, but that's not uncommon at the higher end, with each brand offering different aspects, that will suit different tastes.
It's especially true when working with the mofe expensive film/paper and foil capacitors.
A lot of people tend to go one of two ways, especially with the tweeter cap, Miflex KPCU or VCap ODAM.
If you want a smoother, richer presentation with a very wide soundstage, then go for the Miflex caps.
If you want more precision and focus, with a better sense of depth and layering, go for the V-Caps.
You can also attenuate the sound of the main caps using bypass caps.
Danny's NX-Treme use a Miflex cap bypassed with a Gen 3 Sonicap, which improves clarity and focus, while maintaining the wide soundstage and richness they offer.
Many who go the V-Cap route recommend the 0.01uF JDM silver bypass, which will further improve clarity, but may be bright or hard sounding to some, especially on a more revealing system.
A 0.1uF JDM copper or Miflex bypass, are also options to add a bit of smoothness to the tone.
