There is no 'one size fits all' answer for this. But here are some things to consider:
1. Will you be covered under a tax equalization program by your employer? If so, they will calculate your tax as if you were still in the US and use hypo tax and a tax equalization payment to adjust accordingly. In this case, the MadFientist's recommendations probably still apply since you're essentially being taxed in the same way as the rest of us in the US.
2. If you aren't in a tax equalization program, and all of your income is going to be sheltered by the FIE, I don't think it makes much sense to put pre-tax dollars into a 401k. You're essentially taking tax-free dollars today and turning them into ordinary income dollars later. That's kind of the opposite of what we typically try to do.
2a. That being said, I might still do enough to get the employer match. If you can put in 6% and get a 6% match, you've gotten a 100% guaranteed return on your money. That seems like a positive result, even though the funds will be taxed as ordinary income down the road. There's probably some value in the tax-deferred growth aspect as well.
3. It is possible that your 401k contributions will reduce your local country tax liability. This is completely dependent on the tax treaty between the US and your local country. If you can get the local country tax break, then you'd have to look at your local country tax rates to determine if it is worth it. If you're being equalized, then this will have no impact on you, but may save your employer some money. If you aren't equalized, then there may be savings directly to you.
4. What kind of assistance can you get with this stuff from your employer? Some employers are obviously better / more willing to provide assistance on these types of questions.