can thiel cs 2.4 rock

Thiels need lots of clean power. I dont think Thiels are a hard rock speaker. More acoustic, jazz & classical.
The bi-amp/single amp debate is an ongoing argument. I think it all depends on what your goals are when bi-amping vs running a larger single amp.

First of all, Thiel 2.4's are great speakers, but they do demand a couple of things:

1. Lots and lots of good clean power like Apachef1 says.
2. A big enough room for the drivers to integrate well at your ears, at least 8-10 feet away from your listening position.

Second, what kind of hard rock are you listening to? Is it mostly compressed and/or have instruments recorded out of phase? I brought three co-workers over last week and one of them wanted to hear Smashing Pumpkins. He wanted to hear "Cherub Rock", so I played it. After he heard it, he said that he couldn't tell any difference between my system and his Ipod. He was right.

Now that had nothing to do with the system or the speakers, it was the recording. If you listen to music that is compressed and/or recorded with out of phase guitars, then I wouldn't spend the money on the Thiels or anything in that league. You won't be able to hear what the speakers are capable of.

The better the speaker, the better the ability to reproduce the recording, but that's its limit: the recording.

I owned a new pair a few years ago & ran them w/all the right stuff (at least I thought): Pass X250, X preamp, Cary 306 cdp, Cardas Golden everywhere & couldn't listen to half of my cd collection. If the recordings were less than stellar, the reproduction of the music was way too harsh & fatiguing. they were incredible imagers & really good on great recordings but overall not my cup of tea.