Novice budget audiophile seeks advice on Heresy II

Thanks in advance for taking the time to lend me a hand. I am an entry-level audiophile on a fairly tight budget. I just purchased a pair of Klipsch Heresy II speakers, and would appreciate some advice on them.

Here is my system:
NAD Int. Amp. C320BEE
Marantz CD5003
Pioneer graphic equalizer SG 9500
Klipsch Heresy II speakers.

Here's my question. I like the sound of the speakers, but I think I am hearing a little mud in them. Is there anything that can be done about this? For example, would it help to have the crossovers recapped? If so, can anyone recommend a place to send them? Or, for another example, I've read that adding a subwoofer makes the Heresy IIs play more clearly. Does anyone recommend this? If so, could you recommend a subwoofer that matches my system?

Thanks again for taking the time to answer.