No worries, 6 ohm speakers won't be a problem for this receiver. The spec rates the distortion
figures for 8 ohm speakers, but if you look further in the specs you'll also notice they rate 'Dynamic Power per Channel (8/6/4/2 ohms)' as 140/180/210/250 W, respectively.
That means you could run speakers as low as 2 ohms (since they publish a rating for that impedance). Your 6 ohm speakers are well within the supported impedance range. No worries!
Oh, and I also snapped up one today at that price. Timely, too - I had just noticed the display was starting to fade out on my good old & venerable DSP-A3090. This just happened - after being in continuous duty powered-on 24/7/365 for 8 years (!) and working fine, then was demoted from my HT setup to my computer lab because it lacked HDMI-switching. Since taking up lab duty it gets used 4-10 hours a day. Still sounds good but has had one analog input fail (and now the display) in >12 years service...a well-built machine.
So I was considering a replacement soon anyway...woke up at 8:30 this am to a nice surprise! :-)
Yep, it's always better to use a wired-LAN connection rather than a wireless connection, for reliability when streaming, updating firmware, etc.
More and more (most) consumer electronics makers don't provide a hardcopy of the user manual these days; not only 'be green' and save paper, but so they can make immediate updates and corrections to the manual when it's kept online. Of course, they can also
track how many people are accessing the manual, do some data-mining on you when you hit the site and download the manual ...the Infomatics/e-Commerce thang. They all pretty much do that now...and you know they are doing it, if they make you log into their site first before you can access the manual.