There's more to this than just money. Will the position allow you to get more experience than you would get back home in the same time? If so, look upon this as an opportunity to accelerate your careeer progress.
You don't say how old you are or if you have dependents but, the opportunity to go and work and live in a country like Indonesia probably won't come around too often and, if you are young and single (or relatively so)then this might be one of the few times in your life when you can do this without having to worry about your wife's career or your children's schooling.
Indonesia is a big place and really interesting in itself, as well as being not too far from other interesting places like Oz, Malaysia and China so you just might be able to factor in visits to these places during your stay in Indonesia.
You also need some sort of exit plan, written into your contract, which MUST be with the company in your home country that wants to send you there. Don't sign up to a deal with an Indonesian company - if there are problems, you have to work the issue with them and as a foreigner, it could be difficult. Just in case things don't work out, the deal should include travel to back your home and good medical cover.
Don't buy into the local salary thing unless there is something really atractive about the position. If they want to pay a local engineers salary, then they should get a local engineer.
If its a serious proposition, you could ask for an initial visit of say 2 weeks, to make sure that you like to place and get on with the people