Need HELP with center channel choice

Overpowering? Sounds like nonsense to me, since you will calibrate the front three speakers to the same level anyway. Furthermore, as you may know, the center channel is the most important for home theater, so you want the best center speaker you can get.

I agree, the part about overpowering is nonsense. A perfect match would be another 683 but the HTM61 will be as close as you can get in a conventional center. The HTM61 will be a better match to your 683s than the HTM62.

Everyone you ask will tell you something different. In the end you will still have to make a best guess judgement. What I can tell you though is that typically the center channel is something like 13db down from the LR fronts. That means that it is only getting a small fraction of the power that the fronts are receiving. In this scenario Mtrot's statement is incorrect. -3db is half the power and +3db is double the power. Also, in theater configuration the center channel has no requirement for any real bass so typically you don't need anything large.