Tube Integrated Amp to Drive Floorstanding Speakers?


forgive me, but i'm a relative newbie to audiophile concepts.  i am looking to build a 2 channel system for music that i can grow with.  currently i have a VPI Prime, Soundsmith MKIII cart.   I'm using a vintage kenwood KA-9100 driving Elac Uni F bookshelf speakers for my office.   

in the future, i plan on a listening room of 15x20, give or take.    I am intrigued by integrated tube amps - looking at all sorts, including PrimaLuna, VPI 299d, etc.   but these amps have lower WPC outputs.   I'd like to grow into a floorstanding set, something like the Monitor Gold, KEF R-series or PBS Imagine T3 range.    My tastes range from Classical to Classic Rock.   i do not blast music by any means.    Is an integrated tube amp (35-40 wpc) sufficient and will it leave room to grow?   ideally i'd like a home threater bypass should i decide to add TV that into the mix
mjb87062017
thank you all- i appreciate the input.  to be clear, i'm at the research stage, by no means ready to pull the trigger on anything.   I just wanted some input on the possibility of using a tube amp, and you've answered it.    where i live (Long Island), it is geographically difficult for me to demo speakers or amps, so i thought it might be wise to plan to acquire amp and speakers simultaneously as i'm sure i'll be working with an online dealer.   thanks 
Just make sure that "on line dealer" has a good return policy. What he recommends might not be to your tastes in sound or may not work well in the room you put this system in. IMHO.
You have a wonderful integrated already. Get it serviced/recapped and it will drive the speakers you are considering and do it with finesse.  Those Kennys are special.  The Primaluna amps not so much (at least the Prologues).
Dude, you live on Long Island NY and you think it's difficult to demo equipment???  Plenty of dealers on LI, and a quick trip to NYC opens up tons more options.  It doesn't get much better than that for hearing equipment.  C'mon man!!!
Well, there is Audio Den on Long Island and a whole bunch of dealers in Manhattan.
I would suggest contacting Audioconnection in Northern NJ. Johnny Rutan is one of the best dealers in the area.
Bob