I have a 2007 TL with build in Nav and sat (XM) but it lacks USB capabilities, so I need your help, what is the best USB (not iphone/ipad) interface out there.

I would like to load a couple thousand songs on a USB drive (2 TB of flac songs) with full tags and then use the Nav to search and play (tags, playlists, etc...) alternatively I can convert them to mp3 and put them on a stick but I still want to use the nav and not treat them as CD's.

What do you guys recommend, I have no desire to ever own anything apple so not interested in controlling an i* only USB