For a newer unit it not that bad sounds pretty good

This seems to be the last Aiwa model before Aiwa was fully acquired by Sony in 2003.

I have seen service manuals for 2003 Sony manufactured Aiwa cassette players (though I believe these even later models were only sold in countries other than the US or UK).

Your HS-RX658 has the "Aiwa No. 1" sticker-my HS-JX849 also has the same sticker.

Here is my Aiwa HS-J415 a much earlier model interestingly also with same AIWA No. 1 sticker. My best guess is 84 - 87 so a early use of that sticker. Unit is actually quite heavy and pretty good sound though belt is beginning to give up the ghost.

Here's a photo of the back of my HS-JX849-a earlier model from the 1990's showing the Aiwa No 1 sticker:


I don't know the exact year my model was released in though.

Also my HS-JX849 has the heads arranged in a similar position just like the HS-RX658.
I noticed JohnEdward's HS-J415 has the 90's Aiwa logo,so I'm guessing his unit is from the early 90's-maybe 1990 or 1991.

On the HS-RX658-is the Super Bass adjustable?

I have a 1999 HS-JS175 that has this also-but idn't adjustable (only has a switch on the rear that turns Super Bass on or off).

Same on the RX658 bass is etheir on or off I am going to say 1995-1999 use the same remote from those years retail price was $149.99 then drop to $99.99 when it came out. Unit never been used was brand new in the box.

When did AIWA change to newer logo?

Aiwa changed its several times-first in 1990's to the lowercase "aiwa", and then again in 2003:
http://en.wikipedia.org/wiki/aiwa

Thanks AA

Aiwa changed its logo whenever the JX707 came out because there are two versions of that model floating around, one with the upper-case logo and the other the lower-case wordmark.