Well...
...insofar as info is concerned, this site's FAQs and other sections have a great deal of info de-mystifying the whole A/V deal...and of course, you can simply ask questions in the forums...and remember there are NO dumb questions, only dumb answers...we all had to learn somewhere. BTW, "spl" is Sound Pressure Level, it's measured on a scale in dBs(decibels) and read by an SPL meter...most associated with room equalization and the like...simply, apparent loudness levels, threshold of hearing or threshold of pain and all things in between.
Other units in or about your price range are: Onkyo TX-SR503 @$299, Yamaha HTR-5840 @$350, Marantz SR-4500 @$359, Denon AVR-1705 @$399 and for a bit more, Harman Kardon's AVR135 @$450. All prices are MSRP and in USD...you might do better by shopping around, but be sure to purchase whatever you get from an authorized reseller. Similar units, some have more "adaptability" than others, so investigating each model, as to your requirements or potential for future growth, is certainly in order.
I have an Onkyo 2ch receiver(part of the MC35TECH package) that's seems pretty good with their WRAT technology, the Marantz units have a 3-year warranty, which is why I purchased their cassette deck...Denon is well respected, Yamaha seems to be a fave 'round these parts and HK is another popular(if pricier-for entry level) brand...and while it probably means very little in the grand scheme of things, I have an HK Citation 19 power amp that was purchased in the late 70s/early80s(sometime around there-duh!!!) that's still alive and kicking, in my stereo set-up...
jimHJJ(...good luck...)