I think the 52, at the time I checked a while back were 1K, the 52SE were 1400.
The 52SE is a completely different speaker, and is WELL worth the extra money. I use the 52SE and auditioned both along with B&W 705, studio 20 V3, (along with the older predecessors to the B&W and V3 studio series, but they were bested by the newer stuff).
The 52SE has a much better tweeter, and the bass driver from the contour 1.3MKII. It is an absolutely fabulous speaker, and probably the biggest bargain in the dynaudio line, IMO. Definitely a worthy leap from the 52, which is on it's own a great speaker.