VTL MB300 Delux modded vs MB450's

So here's my issues.

I have a friend that is willing to sell me his MB450's that have the signature transformers, etc and all that jazz for about 600 bucks more than what I could get for my MB300 deluxes.

My amps had all the mods done, sig transformers, B+ fuse, etc and the only thing needing replacement would be the binding post as they could be a bit better.

I'm not really sure if its worth the upgrade to the MB450's as from what I know there wasn't much of a change.

I'm going to be buying his SoundLab M3 speakers from him as well and this is what they would be running.

I do have a BAT VK31 which is a fully balanced pre. The biggest thing is my amps are not fully balanced but I do think the 450's are. Do you guys think it would be worth the 600 bucks to upgrade or what are you impressions? The 450's are newer than my 300's but I'm still torn if I would even want to sell the 300's as I really do love them and could probably put them in a 2nd system.
These are the "original" MB450's from the '90's, & not the newer series II or III? (I can't get used to the new, "modern" look of VTL gear, I liked that old, funky, industrial look). Also, do you have a definite buyer for your MB300's? Selling giant tube amps is not always the easiest.

Also, have you called VTL to ask your question? Bea is (or was, when I owned VTL gear), a great person to ask about any VTL issues.
After I had the VTL Deluxe 225's, I got the VTL Deluxe 500's and, then, the MB450's to compare. I decided I liked the 500's and sold the 450's. After a while, I saw a killer deal on a pair of 450 signatures with MIT caps, got the bug, and bought them. After a few months, I sold the 450's again.

This is not necessarily a matter of better, but different. The only way to know is to compare them in your system. If it is a friend, he ought to let you try them out. Intially, the 450's wowed me, but I kept coming back to the 500's, so do some extended listening.

The 450's have greater resolution, tighter sound. IMHO, the Deluxe amps have more of the tube magic I like. Some would say that is distortion. So be it. Certainly, there is the power difference, as well.

This is a matter of personal preference and only you can decide after hearing both.
I didn't call VTL at all. I have called them in the past and really the biggest response to any question was along the lines of buy our new amp. Or at least thats the way it felt after I asked how much it would cost for them to do a check up on the 300's.

The issue the person who I would get them from lives in GA and I'm in WI. If I bought them I would do it when I pick up the Soundlabs. I don't have time for awhile to be able to go out there before the purchase to demo.

In the long future I would love to try out a pair of the 750's or some of the other higher powered stuff as I love the sound I get out the VTLs.
I have used Mb450s with my SOundlab A1's with great success. They sounded great, and later I moved to the MB750s.
Unhappily my experience with the 300's was with the original MB300s without the signature transformers. The MB450s were much better in all areas I can remember. IMHO, the A3 will also appreciate the extra power of the MB450.