How can I improve my system

You can do your own room analysis.There are numerous set up theories/formulas you can look at on the net - Cardas, Physic's, Donlevy's (as they applied to his speakers) and Rives has a CARA program on his site which allows you to plug in your room dimensions, speaker brand, and it will spit out a suggested starting point. Just a starting point! Use a SPL meter and a test disc with 1/3d octave pink noise to dial in your bass which you accomplish by speaker movements as well as listening chair movement, and when accomplished use your ears to fine tune imaging (mid/upper ffrequencies) by either toe in or room treatments to reduce reflections from side walls, floors, etc. This is not a plug an play process. Its going to take a long time with patience in listening and speaker/chair movements. You make a lot graphs showing the results of different placements so you can learn about your room and placements. It will help you in understand things about your room/set up sound which are susceptible to change and which are immutable. IMHO this is one of the most rewarding things you can do in audio unless you are capapable of making your own equipment. :-)

If you want to get some user comments/suggestions just list your room dimensions, describe your furniture types, rugs, bookcases, etc, their location, room openings, and windows. Folks will be happy to give you some recommendations, which will serve as a rough guide.

As a Silverline owner let me say that I think your speakers are about the last thing I would consider changing in your system. I totally agree with Tvad's comments. I almost bought them, but I selected the Boleros in the end.

Edorr- Peruse some of the info on this site for enlightenment: (http://www.asc-hifi.com/acoustic_basics.htm) Enjoy the experimentation!

Edorr- I should have noted: Your treatments don't have to be as expensive as what's on the site I mentioned. If you type "acoustic foam" into the search bar on eBay, a ton of treatment alternatives will come up. To find your primary reflection points: replace your speakers with a pair of lamps(the bulbs should be at the same height as your tweeters). Sit in your exact listening position, and have a friend move a mirror along the walls(behind the speakers and both sides)at the height of your ears. Anywhere that you can see the lamps reflected in the mirror, you need to apply some sound absorbing or dispersing material. The ceiling will have reflections also, if your speakers have a wide dispersion pattern(a little trickier to find, unless your friend is Spiderman).

Nothing wrong with your set up, but those modest 10K Thiels are pretty good speakers. Just my .02.