I have yet to find a reason for a cooler. I have done the brakes out of necessity but cannot justify the expense of a cooler when the temps I`ve seen on track are perfectly manageable. I like you have the car for road mainly ( as a weekend toy ) with the odd trackday thrown in. I would sooner use the money for the cooler to book 4 or 5 trackdays. Even if it is a particularly hot day and the temps start to increase , so what. The trany fluid change is no longer the £700 domain of HPC`s but remains the stuff of internet scare stories.