[ctuna]

Hi Fi is not the Radio Hi Fi is the sound system . = speaker and amp's or lack of amp.
The Radio as you call it is either idrive or Professional Radio.
When you say you have no Nav doesn't nail down if you have idrive or pro radio.
Although most people would deduce you don't have idrive it's still nebulous and questionable.

Sound systems are defined by the Speakers and Amp if any .
Head units are the thing in the dash.

BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/attach...1&d=1209780865
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/showthread.php?t=641323
http://www.e90post.com/forums/attach...4&d=1278871872
http://www.e90post.com/forums/showthread.php?t=343673
https://www.bimmerfest.com/threads/e...n-752.1275694/
base system wiring pre/post 3/09
https://www.google.com/url?sa=t&rct=...tDpLJPcGkw_ui_
Base System Guide
http://www.e90post.com/forums/attach...5&d=1493273253

If you have idrive it consists of a screen for the hump in the dash and control unit that goes below.
In the US it will either be CCC or CIC depending on the year.