[E90_M3_Dubai]

Oil cooler on its own won't reduce your temps, it will only help to recover back to your "normal" temp quicker than OEM cooler.

Now with FI on an NA engine, you will be producing more heat and your temps passed 220 while cruising in hot weather is believe it or not your new "normal" temps ( as in after the SC install).

now how to reduce that is where you want to focus , and I suggest getting a gauge of some sort to monitor your water and oil temps as a first step so you would accurately check whether the mods are helping you reduce temps or not , the cluster gauge isn't gonna cut it for an FI setup.

Things to do :
1- replace coolant water in your system with a 50/50 BMW coolant and Distilled water mix plus 2 bottles of water wetter.
2- Get an M24 Thermostate kit and replace your OEM
3- GetEpic Motorsports S65 Oil Diverter Valve Kit from bimmerworld website and replace your OEM one .
4- Get an ICEBOX setup from MRF engineering.

doing this will not only reduce your current Oil temps, but it will also give you a constant edge over bad IAT's and this will dramatically enhance your car performance under boost .