VAFCII..... well this is the worse method of tuning. But... and its a slitely large but; if your doing just simple bolt ons it will be just fine. Like I/E/H etc..its fine. When you start messing with cams etc its not a good idea. It doesn't excactly change the vtec point because it only taps into sensors on the ecu. Then the ecu sort off chooses when the vtec should change over. Which won't be until enough oil pressure is built up in the seloniod. So even if you lower the vtec crossover point on the unit it won't exactly change over until it has enough oil pressure.