I think first step is to try 100% water + 2 bottles of Water Wetter in place of coolant (obviously have to change for freezing temps if you live in a region that sees cold), possibly upgraded fan after that, and then maybe step up to the dedicated tranny cooler. The extra radiator from the perf. kit supposedly doesn't do a whole lot. Also try upshifting on the straights to 6th and backing off some to help with heat if it becomes an issue.
An upgraded oil cooler will help you to some extent, since the turbos are cooled by coolant and oil, cooler oil will mean that more heat can be transferred to the oil, and by extension less heat will be transferred to the coolant.
I can get about one, maybe two full sessions in before I limp due to coolant temps. Its frustrating because it ruins your mindset and consistency.