Probably couldn't trade them in, but you'd definitely be able to sell them on the forums. The street kit I had on my Bronzit sold in less than a week (obviously I wish I hadn't sold them now, but what are you gonna do). If later decided you NEEDED the bigger brakes, didn't just WANT the bigger brakes (or just want for bling, I'm OK with that), you could sell the brackets and calipers, then someone could buy new pads/rotors. And you put that money toward one of the larger kits. Really though, trust me, the Street kit is a phenomal upgrade over stock in terms of feel/modulation, not to mention power. That's why I can't wait to see what they feel like on my lighter slicktop M42 car wearing proper sticky tires.