Doesn't matter if it is "replacement" or "reform". No matter what vessel is used to generate revenue for the fedgov is there will be the equivalent of the IRS to oversee the collection of such revenue.
I'm actually quite in favor of the FairTax as a possibility, but it won't get rid of the IRS.
The only fair tax is sales tax as it is consumer based. Property tax is not fair. Any form of income tax is not fair. Don’t nurture parasites.