Don't have a cooler, but I've been doing the Mustang-5.0-oil-filter-on-a-2.5-Wrangler thing. Using the Mobil 301 filter and engine oil capacity has gone from 4 to almost 5 quarts as a result. Cooler oil? Nah.
But its basically 5 quarts taking the stress of the normal 4, so it probably ain't a bad move.
Thought you mounted oil coolers near the front of the radiator, or is that transmission cooler I'm thinking? :?