I'd agree with audiot servant that if you are predominately rock oriented, 3.7s might not cut it. They do have quite a bit more slam than 3.6s...but still no body-blows from deep bass.
If you like the overall sound of 3.7s, then matching with a good sub (or pair of) would be a consideration for sure.
I do run the 1ohm Cast resistors on the tweeters.. the high end on these 3.7s "should" be magical all else being equal. I listen to a wide range of music for hours on end, and these are the least fatiguing speakers I've ever owned. just my 2 cents worth.
