Is it a good idea to add debt during a divorce to reduce the alimony I'll have to pay?

Yes. It is. Better than that is to skip the country and go where there's no extradition laws. You shouldn't have to pay an ex money .... especially if it's not child support and only goes to the ex. That's extortion and just because it's legal doesn't mean it's ethical. Nothing wrong with trying to evade a bad legal decision. 

My advice is to pay zero alimony, stop working or work for cash only, go on welfare, change your name and move away, until your former wife finds some other sucker to take care of her and her kids...

Your INCOME is what child support is based on.  AKA your tax return.  They Court doesn't care how much debt you're in.  That's your problem.  

no , the court does not care about your debt 

you made a bad marriage , do not make it worse on your self with debt 

you will have to deal with this for years to come 

be smarter than when you got married and realize the court again does not care if you can live or not they are saving the world from "evil" men 

never trust a women again,, make sure they always have good long term jobs if you are involved with them and they have no debt and never ever complain about their ex 

SO yes wait till after and then pay cash or do not buy

It's a good idea to ask your attorney such questions as in some states making large purchases with marital assets during a divorce can be viewed as fraud.

Ask your lawyer.  The courts know about tricks like this and may take punitive measures.  Your lawyer can best advise you.

It's never a good idea to add debt at any time in one's life.  The borrower is always slave to the lender.  You are not free when you are in debt.

As for the other stuff regarding divorve I have no idea.

See your lawyer. why are you going to pay alimony? hope you have a lawyer.

You won't reduce alimony, but you should 

get it now anyway, as the alimony payments 

will affect your credit-worthiness afterwards. 

The car is an asset which has a value.  Therefore the total asset after buying the car only alters if the car has devalued first.  It cannot affect child support which is determined by income, and it cannot affect dividing matrimonial property.  Civilized countries don't have alimony.