They are a pretty little boat. But these numbers:
Specifications for the Edel 665
LOA 21.8 ft. LOD 21.8 ft.
LWL 18.2 ft. Beam 8.2 ft.
Draft 3.2 ft. Displaces 3,484 lbs.
Ballast 882 lbs. Mast Height 29.8 ft.
Sail Area 211.0 sq. ft.
D/L 258 B/D 25 % SA/D 14.7
Comfort 16.2 Capsize 2.17 L/B 2.7
.. indicate a pretty heavy boat for its size. With a Cat 22 at 2500#, Oday 222 at 2200#, Tanzer 22 at 2900 all with similar sail area this makes the Edel look a bit overweight - which will affect boat speed to a degree in certain conditions. The other stats don't point to exhilarating performance either.
However if you're not racing, this could be a comfy cruiser in that size range though probably tender with only a 25% ballast ratio. The layout is a bit unconventional with what appears to be a single forward rather than a V berth but the main salon seems to make into a decent double.
Here's a bunch of links with pics and data (you've probably seen these already)
edel 665 sailboat - Google Search
I've not sailed one and am just going by the "numbers' but do recall a fairly nice fit and finish when they were new. Not many around either, but I'm assuming you've found one locally?