Then we'd have to see if these guys actually follow through with their tough talk about cutting spending. My guess is they don't since they are full of crap and only complain about the deficit when a Democrat is in office. But let's say they do. Then we get an increase in the unemployment rate over the next two years as we learn another lesson from Europe that austerity in the face of a sluggish economy leads to stagnation.
They'll try to ram through a repeal of Obamacare through reconciliation since they won't have the 60 votes in the Senate needed to get a full repeal. Doing it that way means they can only go after the budgetary parts of Obamacare, and not a repeal of the whole thing. They can get rid of the penalty for not having insurance since that is a tax and can be considered part of the revenue side of the budget using reconciliation. But they can't undo stuff like the ban on discrimination for pre-existing conditions, the coverage of children until age 26 on their parents plans, and the 80-20 rule for insurance companies. They can undo the taxes on cadillac plans and medical equipment, defund the exchanges, and make cuts to the medicaid expansion. Of course all the stuff that hurts the insurance companies bottom line will still be in place without the increased participation from the people being required to get insured. So that will create a clusterfuck for private insurers. Meanwhile they don't have any plan of their own to put in it's place, so calls for healthcare reform will become an issue for elections again.
If they go through with the spending cuts the base has been screaming for, then we go into the 2014 midterms with an unemployment rate above 9% in the middle of a new recession which they will attempt to blame on Obama. The people don't buy it, and the Democrats win back the House majority with a close margin of about 225-210 due to the 2010 census gerrymander that protects a lot of Republicans. Democrats hold all their Senate seats except West Virginia, but they pick up Kentucky defeating Majority Leader McConnell, and the open seat in Maine after Collins retires. This means the Senate is a 50-50 tie for the next two years, but will most likely go back to Democratic control after the 2016 election.