PrimaLuna Preamp Upgrade Question

I have owned a PL Evo400 Integrated for the past few months. I love the amp, but am considering diving deeper into separates. I've been eyeing a Primaluna Evo Preamp to hopefully unlock more separation and presence.

I'm curious if anyone has any experience with owning a Primaluna Integrated and then adding a Primaluna Pre Amp using the HT bypass. I understand this is a possibility, but I'm curious of the added benefits and or drawbacks. Is there is a general consensus it would be greatly beneficial, I would eventually sell off the Evo 400 integrated and go full separates. 

If you don't have specific experience with PrimaLuna but have been in a similar situation using a bypass in an integrated I'd also love to hear some feedback. 

And here is the setup. I would appreciate any and all feedback. The more I can learn the more I'd love to pass on.
If you like to listen to all genres and sometimes crank it, sell the integrated, buy the preamp, and get a hybrid tube/SS amp like the Rogue Dragon that has high input impedence and damping factor, and big watts, then listen as your Focals suddenly become everything they can be. Room treatment like bass traps would be necessary though too. You can thank me later.
J-wall, you mentioned the GL KT-88 and Mullard 12Au7 combo earlier in this thread.  After auditioning several tubes in my EVO 400, I am happy to report that the aforementioned combo is absolutely killer.  To my ears, in my system of course.  Strongly recommend.
J-wall, if I measure to the face of the foot like your photo, I’m at 3’-3".
From what I see your setup is good. 
I did exactly what you are considering. Was a PL owner for years. Prologue 2 integrated to Dialogue 2 integrated. Then decided to go separates in phases and bought a used PL preamp and ran it through the Dialogue. It was a lateral move. Then bought a PL power amp and sold the Dialogue 2. Used it for a few years. What jbhiller said above was my case. I bought a 6SN7 preamp and 6C33C based mono blocks and quickly sold the PL amp and preamp. In my system the 6SN7 preamp made a big Improvement in sound. More open and natural. Separates offer me more flexibility and I have a separate backup amp and preamp should they be needed. Both my main and backup preamps are 6sn7 based. My system is here on Agon. I finally arrived at the sound I want. It is customized to my ears. I am extremely happy and greatly enjoy my lps and cds. Good luck and have fun!