Although Sound Labs aren't a benign load, they're nowhere near as tough as they used to be, thanks to the backplate update which became available early this year and which reduces the impedance dip in the midrange that some amplifiers have problems with. Great amplifiers for driving them can be found for under $6000. Scintillas, on the other hand, drop to somewhere in the range of 1 ohm and are about as tough a load as any speaker out there. Very few amplifiers can drive them well. They can be a bargain, but it's important to keep in mind the company is long gone and you may find yourself on your own to service them even though parts may be found occasionally.