They're a waste of money. All they do is modulate the signal coming from the MAF sensor. Thus the trick the ECU into thinking it's at another part of it's fuel map. The problem is it also causes the ECU to modify your ignition timing as well. In terms of reading sensors you'd be much better off spending your money on ECU diagnostic software and a laptop interface cable. If you really want to 'tune' your ECU then get an AEM EMS....but again that's overkill unless you've done alot of upgrading. A chip and a boost controller are a much safer and effective purchase.
"The 300ZX Turbo is a dance; it's a song; it's rolling, roaring automotive art. There is no color that doesn't suit it. There is no mood-lifting chemical substance it can't replace." - Automobile Magazine
