Senate Republicans Tuesday detailed their plan to overhaul the state's tax code.  Chamber leader Phil Berger and others discussed the framework of the plan they say will cut taxes by more than $1 billion. Income tax rates would fall over the next three years and the combined local and state sales tax most consumers pay would drop to 6.5 percent. But the overhaul would make North Carolina's sales tax base one of the broadest in the country by eliminating exemptions and expanding to cover more services. Any plan also must win support from house Republicans and Governor McCrory.