Mike, as usual, your explanations are top notch.
In my case, the ambient here in Durban, South Africa is worse of than the UK.
As an example, today was a 33degC high, 22deg Low.. Humidity 89%.
My IAT on highway cruise was between 40-50deg, it only drops by 5deg on a WOT pull. FMIC is a Greddy Spec LS.
Even on a cold day IAT is similar to above, never returns to anywhere below 30 deg in any usage.
The stock sensor location may be playing a role in this though.
Reading the above, the big Con for me will be the easy to heatsoak on the Whiftbitz, looks like ETS is the way.
Thanks again Mike, the details you provide are very valuable, much appreciated.