VTL 5.5 questions

Would the 5.5 be a significant upgrade to the 2.5?
Is the phono stage respectable?

I'm looking for a single box pre/phono stage. I like the having a tube pre, but don't necessarily like tubie sound. The VTL house sound appeals to my rock/punk nature. I plan on purchasing a VPI Scoutmaster/sds in the near future and it's my feeling that the 5.5 will compliment the VPI, and will have a similar sound to my Wadia 301. So what do you think?

Current system:
Classe CAM 200
VTL 2.5
Wadia 301
Tannoy 301
LP12/Ittok/Benz Micro L
Monolithic PS1 modded
I'm sure the 5.5 is a great preamp, but another one to consider if you prefer a more neutral tubed preamp is the Herron VTSP-1A. It is universally regarded as being neutral with just the slightest hint of tube warmth. I have one and love it, they often show up here for around $2K. Happy listening!
Check out the Airtight ATC1 phono preamp for sale; it is a very nice unit.
To actually answer the question at hand here....Yes, it would be a fairly significant upgrade. More tubes, upgraded caps, two power supplies (dual mono design, balanced outputs. Also has phase control, a useless feature for me personally, but an addition nonetheless.

Sonically the first you notice between the two is the bass is considerably better with the 5.5, and the notes decay more noticeably. Where the 2.5 will simply play a string of notes (very nicely I might ad); with the 5.5 you know exactly where they begin and end, as well as what they are. Instrument placement was a little better as well, which could just mean an adjustment to the soundstage. IE front to back, left to right.

Its just simply a stronger preamp all around. Not that the 2.5 is bad, it is quite excellent and probably presents a better overall "value", but technically and sonically the 5.5 is better. Whether it is worth the extra money to some is subjective, whether it is better preamp is unquestionable.
I purchased a 5.5 and was planning on getting it with the phono pre installed. I even sold my Cary phono pre. Then I changed my mind and went without on the VTL. I wanted to keep my options open on a seperate phono pre. I figured I would eventually get the bug to upraged that portion and why spend the money on something that you can't sell by itself? Other than that I love my 5.5 and have not heard a VTL internal phono pre, but I have heard that it is very good. Is that available for the 2.5?
Yes, the phonostage is available for the 2.5 as well...You bring up a good point though about not being able to sell separately. I asked my dealer how many they sell of each, IE with and without phono, and they said it is about 50/50. For me getting into a 5.5 itself was a stretch so adding the phono at the time of purchase was not an option, but like you said, it is supposed to be excellent.