Really, that's totally subjective and depends on a lot of things. Get some velcro or double sided tape and play around with locations to get the best results. I haven't heard those newer Eclipse components, so I don't know how strong the tweeter is or the crossover design. Start with the tweeter close to the mid (either in the door or kick panels) and try that for a little while. If that seems too low for you, experiment with dash or A-pillar locations, and try it with regular polarity and reverse polarity (flipping + and - of the tweeter on the crossover) and see if that gives better results. Also, try sail panel or upper door. Really, it's a subjective matter and depends on your tastes and those components, which I haven't heard yet so I can't really go in depth on what they work best as.