I have the Banks Ottomind(predecessor to the Economind) tuner on my '03. I like it a lot. Mine gives about 2-2. 5 better mpg. It works as advertised, but you do have to read the fine print. The 100hp increase is with all the supporting mods(intercooler, intake, exhaust... ) and that is the best gain from an '03 SO truck. That said, I got a best gain of 95hp(w/ supporting mods) at 2400rpm. I have gotten good customer service from them, as long as I call; e-mails seem to get lost. Hope this helps.