I am glad some one was smart enough to ask about these things before they bought them. I´ve seen them all over Ebay, and they are mostly CRAP. The EGR mod is pointless, since your EGR is only open when you are cruising down the freeway. When ever you stomp the gas, it turns off, and when it is on, you conputer leans the mixture a bit to compensate, so no real loss happens at all. As far as the so called timing advance kit, don´t waist your mony. Go to Radio shack an buy a pack of 5K-10K ohm resistors for like .50c and wire on in line with your intake temp sensor, and that´s all you need to do. The theory behind this mod is the added resistance will make your computer think your incoming air is cooler than it really is and it will give you more fuel and advance to compensate, which in reality is all some chips do also. Also putting a cold air intake is essentially trying to do the same thing, only you are legitamitly making the air cooler. So anyway, anyone who still want´s to waste their money can send me a check for $20, and I´ll be more than happy to send you a piece of paper, and a resistor or two, and we will both be happy.