Your making my day at work go by really fast... LOL.
What you can't seem to comprehend is that people including me use piggybacks with GREAT sucsess regardless of how they work, they get the job done. And get it done safely! It's not just a resistor there are other inner workings that you don't seem to understand. Again I've run a piggyback on my car for years and thousands of miles(like many others) and have not have any of the symptoms that you describe. Your comparing a legit tuning company's products to stuff you find on eBay? Come on guy!!
Do some research on the fastest 1/4 mile times set by 335's, you will find a large portion of them are running piggybacks. What does that tell you? Looks like these piggyback companies are doing something right.