I researched this topic in depth last Fall. My car came from the factory with out the oil cooler and I plan to install one soon. As far as mounting brackets, I believe Advan has the best option and one that I would like to duplicate. Creating the oil core bracket like Advans was my next step but I haven't moved forward yet.
I had a mechanical engineer design the t-stat bypass plate like Stett and Advan use. The only issue is it's big $$$ to have the plate CNC'd to test it out. If the plate works out, I could have a batch of fifty CNC'd at a significantly lower price.