the truth about the gain knob

It's NOT a bad idea, correctly implemented. IF the "gain control" is set at a point sufficiently low enough to produce ONLY 250 watts, based on the average input voltage fed to the amplifier by the headunit, then this will be a perfectly acceptable situation. It will simply allow for adequate headroom, and put a clipping condition that much further away from the picture. It is a perfectly safe idea, but it just has to be WORDED correctly. If the "gains" are set using an o-scope, the safe level can be set fairly easily, and as long as that level is never passed, it'll work forever, with never a complaint. I do it all the time in my systems. For example, in my current system my tweeters (JL silk domes) are rated for 75W, driven by (a potential) 125W, my mids (Vifa 4 inch - specially modified by Harmon, nothing you can get) are rated 20W driven by (a potential) 125W, and my midwoofers (Adire Extremis 6.8) are 200W driven by (a potential) 370W. The 10" TCSounds woofers are driven by (either) 600W RMS @ 8 ohms, or I can flip a switch in the dash which activates relays and changes the woofers (they're DVC) to 2 ohm, and the amp then has (about) 1800 to 2000 watts on tap - per woofer. All amps are Eclipse. I don't USUALLY recommend everybody attempt to drastically "overpower" a system to these extremes, I have been doing it for a LOOOONG time, and I can hear drivers in distress, and I have NEVER blown a driver. (I set all my gains by ear, BTW.) I simply state this to show that it CAN be done safely. You are absolutely correct in the assertion of the "gain control" not being a gain control at all. It is a level matching stage.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."