well recently i have noticed that when its hot out or when the engine is hot that i have a lose of power and the engine will pop through the intake at low rpms under a load in 3rd or 4th every now and then not every time and at low speeds in 1st or 2nd it will start bucking, also i drove my buddies gt with tfs heads and all the other supporting mods and i noticed that his throttle repsonse was smoother off idle then mine but other than that my car felt alot stronger !