nightfall OP"Could" be Vanderseen says amps 40-300 Watts into 8 Ohms and they have their own 400-Watt High-Current bass amps.
The Lamms are 18wpc, the Vandersteens need 75-100, at least. That is the issue.
I cannot find any impedance/-phase angle graph on these, so nobody knows what will be good
Like I said best to get something that has no ?? on it for any kind of loading. Like the Gryphon I mentioned, and if your short of $$ for that, get the cheaper Diablo 300 Integrated https://gryphon-audio.dk/shop/integrated-amplifiers/gryphon-diablo-300-integrated-amplifier/
Cheers George