Hi Mike, I bought mine from Jabiru Australia. It is a Niagara Thermal Products part number 20002A. Dimensions are roughly 5.5" x 3" x 2.5" thick, made up of 7 layers of cooling tubes. It looks very like the NDM cooler shown in the Aircraft Spruce website
http://www.aircraftspruce.com/catalog/eppages/ndm.php. It appears to work very well. I have had no problems with high oil temperatures since fitting it, even in Summer temperatures. I think splitting of oil coolers may only have been a problem with earlier Jab engines which had fairly abrupt ports on the oil pump. Service bulletin JSB004-3 (March 2005) describes a modification to the porting plate. Later model engines have the new type porting plate.
Peter Anson
Sonex 894
194 hours