hehe i have no idea how much it wud cost. but the 4g91 head shud be around rm300 i guess..and another info i got frm our fellow zth bruthas is to use 4g91 carb's distributor..that oughtta do the trick..in the long run i guess it shud be ok apart from the idling thingy...heck, i'd do anything to get more power n coolness hehe...lemme check wit my mech first..