well basicaly i hv seen the kembara dvvt fix the safc but the owner has sold off the gadjet due to selling of the car, as for vafc i m not sure bout it will try to check for u guys .. but might need sum time b4 i can really gave a confirm answer..
function of dvvt can b say same as VVT-i kuah... cos born under same mama (toyota own the stakes of daihatsu in japan) if you notice the engine of avanza n kembara r the same engine just diff by the displacement of the engine... this same goes to the myvi...
just for sharing for my experience i hv no problem keeping up wif standard 1.5 vios vvt-i wif my standard dvvt 1.3 on the straight road but due to the weight & staibility of my car was not allow me to going faster.... :P
will try to help out to answer ur question but if i m wrong pls let me know cheers