Backers see the Foxconn project as a can’t-miss opportunity to transform the region’s economy and build an advanced manufacturing hub around the 22 million-square-foot campus. The plant could eventually employ 13,000 workers, some of whom will likely cross the state line from northern Illinois. If the scope of Foxconn’s proposed investment is unprecedented, so are the incentives offered to lure it: $3 billion from the state and $764 million at the local level if the company hits benchmarks tied to jobs, wages and investment. Infrastructure spending approved in connection with the project could bring the total to $4 billion.