What options are there for a newer radio in a 98 ultra?
Will all of the controls still work?
Mine still works but I think I would like to have options for MP3's & CD's

 

Your 1998 should have an 1/8" input jack in the front of the radio face plate. I have the stock radio in my 98 flhtcui and just plug my iphone into it and let it play. You can put just about any single din radio in it and will need the adapters to fit it, wire it, and retain your thumb controls.

 

I think you can plug and play up to a 2005, 2002-2005 should have a CD as well as the 3.5mm input that you have on yours. One issue is that if you have to replace the speakers you need to replace them with 8 ohm speakers, which are unobtanium. You can run the newer radio with the older speakers, but if you try to run the 1998 radio with 2 or 4 ohm speakers you will overdrive them and they will cut out. What I did to get around this was to but a HogTunes amp and speakers. Now I can run any 4 ohm speakers I wish, and get better sound than I was getting from my old speakers.

Like FLHCHAZ, I also just plug my iPhone into the 3.5mm input and play anything on my phone. I can even stream music as well. To keep the battery charged I plug a USB jack into the cigarette lighter, and my iPhone into that.

There are other options, like an after market radio head, and Biketronics adapters to mate up your handlebar controls with the new stereo, but that is out of my price range.

 

When my unit stopped working I went to a Sony after market marine grade unit with the Biketronics conversion for the hand controls. Works great and I'd do it again.

 

Thanks this will give me something to look into.