I have the TVT 265 kit and a sprint booster. The larger injectors are useless without a computer modification (flash) and a good CAI, etc.
These huge injectors really kick in when the Limited is floored and you hit around 60mph. From that point you can hit 120 mph plus extremely fast. They also do a good job straight off the line. Only if you have the appropriate flash done though. You need the whole package.