Subwoofer setup tips vs mfg recommendation

Received an audio product catalog in today's mail that sprinkles in upgrade/setup tips throughout and came to the subwoofer tips. First tip is to place the sub +/- 1" of the same distance from your ear as the midrange driver (of mains) and NOT in the room's corner ("the worst" placement). Second tip is to lay a down-firing sub on its side so the driver faces to the right or left. The above recommendations go against conventional wisdom and run counter to my sub manufacturer's (REL) design and setup instructions. If a side-firing sub is superior (with increased "bass articulation and clarity", wouldn't REL know this and not design, for example, their Stadium model as a down-firing sub? Any validity to these two tips?
I'm sure the good folks who R&D REL are a lot more familiar with their optimal placement than some audio catalog. That being said, the "best" placement is where it sounds "best" to your ears. A little experimentation never hurts.
Yeah, the Mapleshade catalog is always "entertaining".
agree w above, but aligning a sub at the same acoustic center as your mains should help eliminate timing errors.