The Rell administration is open to a compromise with Democrats on its plan to eliminate the property tax on cars, the state’s budget chief told New Haven’s Rotary Club Tuesday.Budget chief Robert Genuario was the featured speaker at a Rotary lunch at the Quinnipiack Club. He struck a conciliatory tone on the administration’s proposal to eliminate the property taxes cities and towns collect on individuals’ cars. That proposal has received the most attention as the legislature weighs Republican Gov. Rell’s proposed $16 billion budget.