I felt there is no other way for you to get the info you were requesting about gear.
The measurements of the gear are different than the measurements of how the gear behaves in a room right?
I advocate getting the room right first and yes, in room measurements can indeed make the trial and error process a bit faster (and maybe even less expensive).
Now, to answer your question to the OP of how to separate the real deal from a fable I can’t tell you a single measurement that will get you 100% guaranteed satisfaction that your money was a good investment. If you know a better way than auditioning it in your own room I am open to trying it.
I would not recommend just taking some expensive speakers that measure well and sticking them in a room with bare walls like some of our scientifically minded guests. For casual listening, fine. For critical listening and professional reviews maybe get some feedback from a knowledgeable third party like Anthony Grimani at www.sonitususa.com or Jeff Hedback at www.hdacosutics.net.