First off, I'm not so sure that it would be necessary to change out the entire system. The entire Sig line is timbre matched and similarly voiced. The ADP1's would serve you fine for the sides. As well, the C1 is one of the recommended matching center speakers for the S2 according to paradigm. It is not a matter of timbre matching, it really comes down to volume and both the S1 and the S2 are under-sized for reference volume in any thing but small rooms, ie.- 600 sq. ft or less. You didn't mention your room size so I can't really give you a solid recommendation except to say that you should be choosing your upgrade based upon the power handling of the speakers considering your listening habits. You obviously like things loud at times. You blew the S1 and it's my opinion there is a good chance you could blow out an S2 at your listening volumes. The S1 and the S2 are fantastic performers, but the S2 has a max of 140 watts of amplifier power, which is more than the S1 but not by much. So, unless you're in a small room I would suggest nothing less than the S4's for the fronts, or just keep the volumes down. 105-110 dB is REALLY pushing the S1 and S2 to their limits which is not a great idea. The S4 and up can do that comfortably with the proper amplification. All the Signature speakers are a great value for the money imo, but if you're going to upgrade, I say do it smartly so you get what you want when you turn the volume up.
It's all just my opinion, but I know what you have and I'm in the same boat. All I want to worry about with my next upgrade are my ears, not the speakers.
It's all just my opinion, but I know what you have and I'm in the same boat. All I want to worry about with my next upgrade are my ears, not the speakers.