Worf,
I don't know what "reference" means. I can tell you however that I purchased a no-name center speaker years ago with the word "reference" on it for $20 on clearance at Soundsaround. It did the job, although it was nothing like the VP150 that I have today.
I come from the school that says as long as an amp is not being pushed beyond its specifications, it should sound the same as any other amp. If you buy a 90W/ch amp, and you are listening to it at 45W/channel nominal, you definitely need a larger amp to handle the dynamics as most of the time you will be listening to clipped music. In my case, I run mine at a maximum of 1W nominal for music so I have about 20dB of headroom which is plenty with the exception of some classical and orchestral music.
Now having said the above, I recently listened to an old Sansui 340W/channel amp with Nuance speakers at my buddy's. The whole system sounded very tight and crisp. However, consider that this was a completely different room from mine and the listening session was not controlled. I therefore am not going to jump to the conclusion that the Sansui is somehow "better" than my Denon for my application. What I plan on doing however is bringing the Sansui to my house and A/Bing it with my Denon under more controlled conditions.
