I don't mean in that aspect. but having a dual income vs a household income of 7~8k/mth do make a difference. household income of 7~8k/mth will sure survive in SG but you should not be expecting any fancy lifestyle. if your wife is not working, I think both your wife and kid can be deductibles when it comes to income tax. check out iras website for more info.

7~8k I mentioned above should be gross (not incl bonus, and no companies I heard of will pay more for your case), if you're foreign you do not need any cpf contributions. anyway, engineering jobs do not normally give out more than a couple months of bonus.