I sold both used and think its more the sound of each speaker. This is evident at low listening levels where both speaker use less than 10 watts and is independent of the loads presented by the speakers.
Also the 3's are more efficient giving 88 vs 86db @1watt/1meter. The 2Ce is 7 ohms nominal,4 ohms minimum and the 3 is 6 ohms nominal 4 ohms minimum.
Recommended amp size is 40-160WPC for the 2's, 100-200WPC for the 3's.
ET