DTTJ ,,,,,,
you are correct ,,,,,,,
if you are going to keep your 1998-2005 Harley radio ,,, you want to use the 8 ohm versions of the J&M 7.25" speakers ,,,,,, and don't worry about the amp, as the J&M amp will NOT fit on top of the 1998-2005 Harley radio anyway,,,,, we tried every which way we could ,,,,
BUT ,,, the performance of the J&M 7.25" 8 ohm speakers will be excellent with the 98-05 Harley radio ,,,, and that is what you need ,,,,,
please let me know how they work for you ,,,,,,