Upgrade Primaluna Dialogue 2 to Dialogue Premium

I eventually upgraded to the premium and found the sound a bit more open and detailed. I also changed the stock Primaluna EL34 tubes to the GL KT-77 and the stock 12AU7 to the Cifte 12AU7 and recommended by Kevin Deal at Upscale Audio. This made the sound more 3D and a larger soundstage. 

Was it worth the price difference? Was it a small or large improvement?

I have the HP integrated. Upgraded from the Prologue 2.
Its a fabulous piece that I found lives up to its Stereophile review and owner raves. 

Asking if it's "worth it"or a small/large improvement  really is subjective. You may need to do an A/B comparison to really determine if the improvement is worth it to you.

I can only imagine it's an even tougher call since you have a Dialogue, which already rises above its price point.
Perhaps calling the distributor, Kevin Deal@ Upscale Audio will help.

I have a DiaLogue One, which I love, paired to a pair of Sonus faber Elipsa SE’s. I got the chance to play with an HP at home for a few days and found the results very interesting. I posted my thoughts on this board not too long ago (you can read more here:

https://forum.audiogon.com/discussions/primaluna-dialogue-premium-or-premium-hp)

...but, in short, I ended up keeping my DiaLogune One. :)

Little improvement....only worth it if you feel the need.  ...an upgrade, but a smallish step.