You'd have to be a lot more specific...the possibilities are literally endless. Some folks say "mods" and they are thinking some new grips and a pair of throw-over saddlebags, others say "mods" and think new frame, custom paint, and a supercharger.
What is your budget? you looking for cosmetic mods, or performance mods? You looking to clean p the looks of the bike, or bling it out? Do you want to make the bike faster, or more reliable, or more comfortable for long trips, or increase the carrying capacity, or increase the storage space, or cut it down to a bobber, or rake it out to a chopper, or make it into a full dresser, or add features not available from the factory, or what?????