@kjl1065 I got the Sbooster MKII for my Qutest, the difference for me is I now use the incisive filters almost all the time. Prior to the Sbooster I had to use the warm filters as I found incisive gave me listening fatigue. I also purchased the Ultra MKII upgrade which is an additional inline filter. I honestly can't hear the difference with this in our out of the chain.
With all due respect to @audphile1, I think what Rob Watts point was that he didn't think a linear PS would improve the sound quality...therefore he doesn't recommend it. Most people who upgraded to one feel it was a positive move.
As mentioned implementing a Sbooster couldn't be easier. Buy the 5-6 volt version. Slide the voltage selection switch on the Sbooster to 6 volts. Attach the included micro-usb attachment to the end of the cable, plug into Qutest and enjoy.