Like others are saying- if you plan on tracking your car, you'll need the oil cooler. If you dont track it, you'll be just fine with JB4/DCI/meth for aggressive driving on the street.
You'll benefit most from studying the effects that tuning to a certain increase in hp has on the components associated with the increased power, deciding how and when that power will be used, and then finally taking into consideration how long you want to keep the car and how much you care about it (or how much certain hefty repairs do or don't matter to you and your bank accounts)
For what it's worth, I tuned my car that still doesnt have an oil cooler at ~26,000 miles. Back then, I got the JB3 2.0 when it was first released, and within the first year I spent more on 100octane to run map 7 with just a DCI than most companies charge for an oil cooler kit. Meth followed when I updated the tune to JB4, still no oil cooler. I also change my motul 300v every 5000 miles and rarely see temps rise above 250. That being said, I take it easy during Phoenix summer afternoons too, understanding what can happen if I'm trying to do tons of 17psi WOT runs when its 115 degrees outside.
Learn and make the choice based on how you plan to apply the power.