They won't help your '01. They are nothing but resistors to fool sensors and though they have some value on older trucks, my experiments and the information presented by others shows they are about useless on newer ones.
Save up and get a real "chip" for your PCM or a tuner to download it. Either way you'll be able to get real, measured gains that you'll be happier with. The stuff on eBay is not so much a scam as a "myth" which doesn't translate to newer control systems.