Help me understand tonearm/cartridge compatibility, please!

Hi everyone,

Once again I'm seeking to educate myself on turntable set-up issues with the help your vast experience.  I only recently came to understand the importance of cartridge loading, and I think I have a decent handle on that.  However, I have been having issues with some new cartridges that I've tried, and my guess is that it is due to cartridge compliance, something I don't have a full grasp of yet.  The following results have held with two different phono stages:

I have a Marantz TT-15s1.  It comes with a tonearm designed by Clearaudio for Marantz and a Clearaudio Virtuoso cartridge.  After I broke the stylus no on the cart I decided to explore some other carts.  I have gotten a wide variety of results, and I am guessing that compliance is the issue.  The Clearaudio cart that comes with the table has a compliance of 15.  

1.  Denon DL 103r (compliance 5)- very thin sound, almost like someone turned down the bass and turned up the treble on a tone control.   

2.  Denon DL 110 (compliance 8)- excellent sound at very moderate volumes - deep sound stage, clear vocals, quick transients.  However, raising the volume to even average levels results in significant high frequency distortion, enough to make things unlistenable. 

3.  Grado Reference Sonata 1 (compliance 20) - this seems to work fine, without distortion.  Frankly, I like the sound of the DL 110 better, but the distortion has let me to stick with the Grado.

So, I am assuming that the compliance of the two Denons is too low for my tonearm and that I should stick to a cart closer to 15+?  

Any thoughts would be appreciated.  Thanks, and happy holidays!
Scott