Ok my understanding for the unichip its a piggyback module that regulates timing, fuel curves, vtec and more (unsure)

Does VAFC do the same? what makes this 700$+ chip/module better then a 250$~ vtec controller that does the same too?

This would be interesting for those who might consider an ecu power adder. like me

 

I wish I could answer this in more detail for you but I'm not familar enough with the VAFC to give you a direct comparison between the two... Hopefully someone else can chime in for you.