Size isn't the real measure of the performance of the cooler. The Ford units are a fin and plate type which provide much better heat transfer than the coil type marketed by supercheap etc.
I have been towing a two tonne plus trailer in my EB and had no probs so far, however the oil temp is still getting high. On the EA I went to the Ford wrecker and bought the Ford oil cooler and all fittings for around $40. However, it will need new hoses when you fit to your car.
My solution is going to be fitting two (in series) Ford coolers as this allows a larger open area of cool air flow to the a/c condensor.
BA'1.5' Pursuit 290
Lightning Strike / Reflective Orange Stripes
'General' Dog - AP's German Shepherd and Best Mate - 02Dec1998-15Dec2003.
'Pepper' Dog - General's and My Little German Shepherd Sweetie - 1996?-02Apr2006.
'Sako' Dog - My Beautiful and Pretty German Shepherd - 2001?-23Aug2006.