Thanks to all. Just to clarify, when the engine was brand new I used the recommended mineral oil for the run in period. I saw very acceptable temps through this period. After 25 hrs I changed to semi synthetic Exxon 100 aviation oil, I still saw very happy temps. Jabiru then stated to use 15-50 for all year round running, not just for winter. Since the change to this oil I see higher than usual temps.
I used to see about 90 deg C in the climb at 90 kts, then in the cruise 60 - 70 deg C.
As I mentioned I saw no need to do the mods prior to this. I spoke with Jabiru and they are happy for me to go back to the semi synthetic Exxon 100, as all was happy then.
I fly out of the north coast NSW which does not get too cold so personally I don't feel the need to use a cold climate oil.
Appreciate everyones input, feel free to comment further.