G'day
The last one i did cost around $350-$400,depending on what sort of alt you have its a simple matter of buying a BOSCH BXU 13012 alt from memory,and if your car is up to VP swapping the internals.
The other thing to do is to run an extra battery feed to the + terminal on the alt to handle the 130 amp alts output.There is a madification that can be done to the alt stator connections (DELTA the connections on the leads) but this has the down side of the alt needing to be driven faster to get it to "kick off" ie to start to charge and requires more revs to keep it charging,so in other words when ya cruisin around with ya DOONK DOONK goin full blast you will need to haver it in 1st gear to keep the revs up :w00t:
Regards. Phillip :wax: