Oil cooler from my StarQuest swap is the banjo ends with tranny hose and double FI clamps at all four ends. That was two years ago now and ~7k miles. I may have but a little flare on as well, can't remember now.

In my case there was no off the shelf pre-bent option, so I did the flex route on the cheap. Seems to be solid so far

Big Truck: 00, 3.5, Endeavor, 5-Spd drive line in hand!
Little Truck: 87, 2.6T I/C, MT, LSDs, Tonneau Top
Her Truck: 03, 3.8, 20th Anniv, 65k
Daughter's: 06 Eclipse, Keeping it Mitsu!
FSMs: MitsubishiLinks.com