V6 Speed Chips

Looking for info on the multitude of speed chips for the 2005 4.0L V6. I see them everywhere and there are many different types, from simple resistors to extensive rewire jobs. All boast the same thing more HP and more MPG. I am very interested in the more MPG's. Do these things work? If so, will they damage the engine?

SCT xcal2's and diablo predator are both good chips but xcal2's will yeild more hp and can remove governets/limiters and make auto's shift faster/harder. $20 ebay chips can damage your engine because the trick the computer into thinking the air coming through the intakes is colder then it acually is. and yes they do work, i have a xcal2 on my 02 and its the best mod i have done

those resistors wont damage your motor, you wil have a nice power gain for aobout 10min..then teh PCM will learn you tricking it and correct itself.

the Escort guys have been using those resistors on a on/off switch for years...no one has hurt a motor (in over 8yrs).

Dyno showed a 5.4 hp/7.7 tq differnce at peak....and a max gain of 14.4 hp / 10.8 tq. at 6500 rpm at points in the powerband.

how ever you can build a resistor setup for $7