All things being equal, James Sibold likes the idea of Dunwoody becoming a city.

"Who wouldn't take a " 'Get out of jail free card' from Vernon Jones and the county commissioners?" he asks.

Trouble is, says Sibold, chairman of the DeKalb County Republican Party, nothing's free, including cityhood.

And residents of the north DeKalb community, Sibold believes, may have to pay more dearly than has been suggested to break away from Jones, the county's chief executive, and the DeKalb commission.

Jones declined comment, a spokesman said.

Sibold, a Dunwoody resident, thinks Dunwoody citizens, especially those on fixed incomes, won't be willing to pay that price. Confronted with the prospect of rising property taxes, many otherwise cityhood-inclined citizens might even vote against an incorporation referendum scheduled for July 15.

He has some numbers to back him up.

A poll of Dunwoody voters, paid for by Sibold and conducted by Ayres, McHenry & Associates Inc., shows that the community's citizens strongly favor cityhood. But, when higher property taxes are added to the mix, their solidarity slips.

According to the poll, 66 percent of voters in Dunwoody precincts support incorporation, 12 percent oppose it, and 22 percent said they didn't know.

If incorporation means higher property taxes, though, the poll found that 39 percent support cityhood, while 33 percent oppose it.

The results were based on polling of citizens who voted in the last two primary elections, in 2004 and 2006.

"The threshhold is whether people are willing to pay higher taxes," said Sibold. "The question is whether you are willing to pay more money in taxes to be be free of Vernon Jones and his politics, and his successor. My feeling is that there is a price elasticity here and at some point that elasticity goes away."

Sibold said a study done for Citizens for Dunwoody Inc., the nonprofit group behind the cityhood vote, by UGA's Carl Vinson Institute of Government seems overly optimistic to him. Cityhood supporters, he said, underestimate the cost of running a newly incorporated community.

"It's all rainbows and candy canes," he said. Sibold's concerns include the cost of infrastructure maintenance and police protection.

Other critics, such as state Rep. Jill Chambers (R-Atlanta), also say the numbers don't add up.

"The Citizens for Dunwoody and the Carl Vinson Institute have not done their due diliegence," said Chambers, who said she would vote against the referendum to incorporate.

Cityhood advocates dismiss such claims.

"(Sibold's) got some reservations about the numbers," said Brian Anderson, a member of Citizens for Dunwoody, "but we're very comfortable with our numbers. All the revenue estimates are conservative, but the spending estimates are not."

Anderson noted one safeguard. Without a separate vote by Dunwoody residents, the city council, according to a proposed charter, can only raise property taxes by one mill, about $40 per $100,000 of assessed value, or about $120 a year on a $300,000 house.

"People on a fixed income have the one mill guarantee which they don't have from the county," he said. "And, assuming you have any kind of fiscal responsibility, you have no need for a tax hike."

Sibold said he personally can afford a hike in property taxes, but that he wants his fellow Dunwoody residents to be aware what they may be getting into if they vote to incorporate.

"I think there needs to be a debate," he said. "Nothing comes as cheaply as planned."