Stock TMIC will limit you, regardless of situation, in how well it cools the intake charge. The hotter the ambient temp, the more inefficient the stock TMIC is. The big problem is that the IAT sensor is in the MAF on a stock car, so it doesn't accurately represent how the stock unit works. An aftermarket unit will have a lower pressure drop and cool the charge better. It's absolutely worth the money invested, if you adjust the tune accordingly.