Didn't want to highjack Wedgie's post, but am interested to hear what type of oil cooler guys are running.

I am thinking of buying one for my car. Does anyone have experience with them? Is it best to buy a complete kit, or can the plate that goes in front of the filter be had for cheap elsewhere? I have never known anyone to run an engine oil cooler, and would like to potentially give it a try. Is it worth it? How much does it really help in taking heat out of the motor? How much will it aid the radiator in overall cooling? Is there a noticeable difference?