Switch from AB to D

I have a Onkyo TX NR 3007 that eats up electricity because of 4 amps inside. I would like to switch to the Vidar class D from Schitt's. I really like what I've read about it and the reviews. I am handicapped and can't get out to listen to any class D units in my area so I'm going to depend on some people here give me a good idea where I'd be going from class A B to class D what's my sound. I will be using the Vidar with a Audio Experience Symphony preamp with three matching Telefunken tubes that have been in there since I bought it and it's serviced me well along with an Audio Experience Concerto Plus phono preamp. I have an older Soto Sapphire turntable with a clear audio virtuoso cartridge wooden body that has been rebuilt by the soundsmith what a great sound. Oh by the way I have an Oppo 103 Player for my digital along with PSB image five speakers which I got for a great deal of many years ago and they still sound good with my system.
So the bottom line here ladies and gentlemen what am I going to experience putting a Class D amp with a hundred watts per Channel in place of my Onkyo with 140 watts per Channel at class A B power?
Thank you much
Ron in Highland Michigan
In my system a pair of DAC Maraschinos, class D beat various A/B amps in several respects.  Tightened the bass and mid bass, opened up the upper midrange, and just more musical sounding.  Speakers are either Magnepan or Martin Logans.  The Cherry amps are not cheap.  You could also try a Crown class D amp for about 200 or so.
Class A/B amplifiers in an AV receiver are usually not biased that high, so the amount of power they draw just sitting there is not very high. What is your power concern? Heat? Electricity bills?
I’ve been very happy with my tiny little NuPrime amps. They have different “flavors” of amps. There’s a matrix on their site to help find the sound your after. Mine are STA-9s running as monoblocks. Very warm like tubes but very fast with tons of grip for bass. I run very inefficient speakers and they can make them beg for mercy if I want to crank it up. On my old high efficiency ones, they can crack windows. 
After having AB for 40 years my present D is the best one I've owned. The last Superphon idled at 90 watts. This one idles at 13.  It plays loud at 30 watts consumption. I "Kiil A Watt" everything.
140 watts X 2 into 8 ohms, 300 X 2 into 4 ohms.  Damping >1100 @ 8 ohms.
PS Audio S300. You can trade in any crap you have laying around at it's MSRP.  Just no pro gear. Paul will ship it to you to try for 30 days. If your ears don't like it I think he will even pay return shipping, Fed Ex.  You can even schedule a home pickup.
If you can wait he does 20% off for shows and Black Friday week. Virtual Axpona is this week. Call and twist their arms. Ask for Joey Fisher. She was sales mgr.
I've met Paul Barton (PSB) too. Great guy. 

Good luck and happy hunting.

I forgot to tell you I'm on a budget sorry about that guys and my Onkyo does not have pre out or main in. 
  There are many good suggestions you guys are give me to wake me up a little bit but I'd like to keep it around $750 if possible. I got spoiled for a while having a a tube integrated amp from Paul Grybeck for about 4 years +-, had to help a friend get some money for his mothers cancer treatment. So I did what needed to be done.
Thank you one and all