The Vandersteen 3A Sig is IMO much better than the 2CE Sig. My brother owns a pair of 3A Sigs, and we listened to both models extensively. Both create images extremely well. In fact, these Vandersteen speakers are the world champions at imaging. I've never listened to the Vandersteen 1s or 5s.
The 2CE Sigs did have a noticeable bass emphasis, that was not unpleasant. The 3A Sig corrected this with improved midrange driver, tweeter and crossovers, creating a better balance in sound, without being too bright sounding.
The price of the 3A Sig is also much more than the 2CE Sig. Be aware that the 3A Sig price includes heavy duty stands, and the 2CE Sig price does not. So add the price of the stands before you compare the prices. You will have to decide for yourself if it is worth the difference. Both of these speakers do well with lots of power, at least 100 watts/channel.
Good luck finding a dealer. Once you hear them, you won't regret the effort it took to find them.