New Jersey has a cost of living index of 120 relative to the US average of 100. This is above the national average. A FIRE portfolio in New Jersey needs to stretch further. Many FIRE practitioners in NJ plan for a higher withdrawal need or consider relocating to lower-cost states.
The 4% safe withdrawal rule suggests a FIRE number of 25x annual expenses. At New Jersey's median income of $87,700, that is $2,192,500. However, if you plan to spend more (or less) than median income in retirement, scale the number accordingly.
New Jersey taxes income at 1.4%–10.75%. In FIRE, your primary income comes from portfolio withdrawals, dividends, and capital gains. Long-term capital gains in NJ are taxed at the same rate as ordinary income, including IRA withdrawals. Factor this into your withdrawal rate planning.