BAT VK5i 6 pack capacitor upgrade

Hello, I have a BAT VK-5i preamp, and I was wondering how much improvement would the 6 pack capacitor upgrade would give.(?)

Another question is, can I apply this mod my self ? I live overseas and I cannot afford sending the BAT to the US !

Does anyone with BAT have performed this upgrade and what was the result ? Does it worth the money ?

Thanks.