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Using an online 2013 calculator head of household status and three dependents with 70 K income and 8K deduction gives about $6200 federal tax estimated.
Changing that to 170K of income gives about $34200 or about $28000 more federal tax.
There may also be a 10% penalty on early withdrawal of the retirement plan when you are not age 59 1/2, disabled or meet another of the exceptions to this penalty.
For a chart of the available exceptions please see http://www.irs.gov/Retirement-Plans/Plan-Participant,-Employee/Retirement-Topics---Tax-on-Early-Distributions
The TSP is a Qualified Plan in the chart.
So including the penalty that would make it increase of 38,000 federal tax on the 100,000 taken.
Michigan state tax is about $2340 for 70K income and $6690 170K income for an increase of about 4350 state tax.
Total increase in tax for federal and state about 32,350 and unless you can qualify to be exempt the additional 10% or 10K penalty gives total tax increase about 42,350 on the 100K.
Total tax due about 44,200 federal and 6700 state or 50,900 on the 170,000 including the penalty.
As you likely know, if there is any way to get the funds other than by a withdrawal that will be better as your tax and penalty could be more than 42% of the amount
At the very least perhaps it could be arranged to take the funds out some this year and some next year to spread the tax and give more time to pay.
Please ask if you need more discussion or clarification.