MTC,
DinkyTown offers some exceptional financial calculators that can help in this decision. The one of immediate interest is the
'Credit Card Payoff' calculator. Using that calculator you can pay off this pig of a credit card bill in two years if you pay $400/month toward it and stop using the card. I would recommend dropping your TSP contribution (if necessary) if the $400/month (not pay period) will be impossible. $600/month kills it in 18 months. Reducing your TSP contributions to 5% is kinda a no-brainer if you have 16% interest rates to pay off, reducing it further is more complicated since you are biting into the 100% instant match growth.
My guess is that you will receive offers for reduced interest rates as soon as you show a big payoff history! They will want to keep you. Don't fall for the trap of bonus points and paybacks - take a lower interest rate.
Don't worry about the car till the credit card is paid off. It is a decent fixed rate. Credit cards are fixed rate in name only. Think positive. If you stop charging on the card you will have no credit card debt in two years and your car loan will have two less years on it. You can apply all/some of the credit card payment toward the card and kill that thing off as well.
And, no, I strongly suggest you DO NOT use a TSP loan for this. Read and listen to Dave Ramsey. You've probably got to get mentally ready and serious about debt management. I lived the dream. I am almost out of debt now - and my situation was far worse. Had I taken a TSP loan four years ago I would probably still have credit card debt to go along with the TSP loan payback. Ugly.
Finally, you have 20 years till retirement (so about 45 years old) and a $100K. If you invest $8K/year (your contributions and the match together) for the next 20 years and increase that contribution by inflation then you will have $930K upon retirement. You will we able to take out about $38K/year pre-tax for twenty years (till 85 - then you are broke). That is $3,100/month or $1,450/pp.
Again, do not assume you are retirement rich and take out 1/5th of your retirement assets to pay off current debts. You will lose the growth on that money, you will refill that bucket with after-tax money, and you will pay interest on that after-tax money. And, this is from a guy who just took a TSP loan to help buy new windows for the house. But, I can pay it off within two years and the amout was only about 3% of my holdings.
Happy hunting.
And, like all hunters, look at your less calorie consuming options:cheesy: