1. What speaker are you using in your current listening or multi-channel, or surround sound system.
Summit.
2. What type of Amp: tube, hybrid, solid state, Class A, A/B, D, first watt, flea, mega watt...
Currently using an Acoustic Research LS26 Mk2 tube pre amp and a Proceed BPA (I've retired my Classe Model 25 due to excessive transformer hum). The Proceed is essentially a Mark Levinson product and is rated at 125watts p/c into 8 oms which doubles into lower impedances. The combination with the ARC is very good.
3. Are you happy with the power capability or SPL (Sound Pressure Level) that you obtain with your current combination?
I'm more than happy with the spl's I get from my amp/speaker combination. I hardly notice the difference in power output from my previous Classe which was rated at 250 watts p/c.
4. Are you considering an upgrade, if so what?
Yes. Like everyone here, I'm always considering possibilities. I wouldn't mind trying tubes - maybe an ARC model. I like the ARC VS55 and the VS110. But I might be stretching the friendship if I tried running the Summits with the VS55. 50 watts of tube power might not be enough to satisfy the Summits.