Should I upgrade my towers?


Hey everyone, I recently upgraded my 10+ yr old H&K AVR and Klipsch Synergy towers with a Cambridge Audio CXR200 and Wharfedale Reva-4 towers. I think they sound pretty good together, but admittedly, I know nothing about sound.
Up untill recently, I mainly was only focused on HT. Now, I stream Apply Music to my CXR200 and I love it! I find myself listening to a lot of music on it. 

Now, I'm wondering if I should upgrade my towers? Am I missing anything with these towers compared to better towers? If I went to say $4k towers (pair), would I get significantly better quality sound? I'm more than willing to buy a used set here on Audiogon too. I would keep my CXR either way. Btw, it puts out 170 wpc in stereo at 8 ohms. 

Any thoughts on upgrading, or just keep what I have? Thanks everyone. 
manofsteelpt
Are you near dealers?
As you said you 'know nothing about sound', it would behoove you to go listening to as many speakers as you can. Eventually, you will find the ones that work with your ears.
As far as brands go:
Vandersteen, Magnepan, ProAc, Zu, would be my choices. Others will give you even more choices.
Be prepared to start changing the rest of the system, once you hear how good the new speakers sound.
B
IMO the very first thing you should do is go listen to live unamplified music!!!Go to a small jazz or blues club,the local symphony,a downtown streetcorner,even bookstores have open mic night.Pick up a guitar.Strum it,even if you can’t play it you will know what the basic sound(tone)is.Like rock and roll or electric blues,go hang out in a Guitar Center on a holiday weekend.I am constantly amazed at the people I hear playing around GC...You need a baseline for what music is supposed to sound like...
gdnrbob... thanks for the suggestions, I will look into them. As for dealers, only BestBuy around me. So, it will be a blind buy. 

Freediver... that’s a great suggestion, thank you too!
You can get some great speakers for 4K. Need to be careful what you are buying with an avr to match well. Should be efficient with not a lot of big impedance dips at or below 4 ohms. 
Any suggestions? I read the Focals are high in sensitivity... maybe a newer version of a Klipsch?