Basic question about impedance and watts

I've heard great things about Thiel's service as well. Good luck to you!

1-you should get as much wattage as you can afford. Thiels will suck your amp dry. Don't get me wrong, I love thiels. However, anyone buying that level of speaker must match it with an equal amp.
2-a little help with wattage:
Doubling the power will get you a 3db gain
Every 10db will double the perceived listening volume
Therefore, a 94db speaker, 8ohms, will produce about 110db at 50watts. An 87db speaker will require about 150 watts to get the same volume.

Ketchup,
model CS3.5
Bandwidth (-3dB) 20Hz-22KHz
Amplitude Response 23Hz-20KHz +/- 2 dB
Phase Response minimum +/- 10 dgrees
Time Response minimum +/- 50uS
Sensitivity 89dB @ 1 watt-meter
Impedance 4 ohms
Recommended Power 50-250 watts
Size 33 X 33 X 107 cm
Weight 77 pounds

When I questioned Jim Thiel about the power recommendations he said that they were given with high quality (amps that could "double down") solid state (standard 8 Ohm) power ratings in mind, and that as such one should double those ratings if they chose to use tubes. Your power requirements will depend on your listening room and desired volume. Bottom line, the absolute minimum amp should be capable of providing 100 watts into 4 Ohms. IMHO you would be best served using a quality (quatliy is the operative word) amp capable of at least 200 watts into 4 Ohms. Plato is right on with regard to the equalizer!
BTW, Thiel recommended a least 1 foot from a rear wall, 3 feet from the side walls, and 8 feet from the listener, set up in an equilateral triangle as a start. Thiel also suggested that 3 feet from the back wall, 5 feet from the side walls, and 10 feet from the listener would be preferable.
Thiel also suggested quality cables tightly connected.
Thiel's customer service is second to none!
Good luck.

Thanks for all the info, guys!
I called Thiel today and spoke to some very nice people. They told me that if I send the EQ box back to them, Jim Thiel himself will test and repair it at no cost. They're also going to send me a copy of the original owner's manual, and they even offered to send me spikes if I didn't get them with the speakers. This made my day!
If anyone knows of any amp companies this helpful I will buy their stuff, but I doubt there are any with customer service this good.
All of the info that you guys provided above matches what Sherry (of Thiel) told me today, such as the amp needing to double down, the EQ box sucking up power, and needing quality cables.
I thought she said they needed 50-350 Watts, though, but I must not have heard correctly. Whatever she did say, (250 or 350) she added that they have used much more powerful amps with great results... so I guess 350W should work :)
Unsound, I'm assuming you have 3.5's? Can you offer any more advice on amps, such as what brands work well with them? I'm already going over my budget and was hoping to only spend about $500 on an amp (used), but if I absolutely have to spend more I guess I will.
Thanks!

Ketchup, no I don't own the 3.5's. Your Thiels deserve a real quality amp. When they were new they were often paired with amps in excess of $3K. Your budget is a'hem, challenging. Here on Audiogon there are a couple of Aragon 4004's for sale, an older Threshold, an older Classe' and what I would personaly recommend (albeit a bit more money) a brand new Sonographe. Good luck.