The '04 has a dry clutch and the '05 has a wet clutch. The ECU and springs on '04's below a certain VIN number had to be replaced (fully covered by Ducati) which corrects the lumpy throttle running at lower rpms, around 4500 and below. This is not an issue on the '05. Hopefully you can verify the work through the dealerships records on the bike or the previous owners. Some bikes it was extreamly obvious if the problem was there and on others (like mine) it was more subtle. One sure way to notice is slow warm up time requiring excessive use of the cold start lever, stalling when coming to a stop after the engine is warmed up, low idle. The '04's needed the gas overflow tube repositioned to move it away from the exhaust (easily done yourself or by your dealer but needs to be done/checked for obvious reasons). Don't know if that was an issue on '05's.
Essentially the same bike other than clutch and some color choices.
Essentially the same bike other than clutch and some color choices.