Regearing both of your axles is the ONLY ONLY ONLY
way to restore the power lost by the larger diameter 35" tires. No engine mod will help... not a cold-air intake, not a gimmick spark plug, nothing on the engine will fix this particular issue. Regearing serves to raise the engine rpms back up to where they need to be to turn those larger diameter tires. The bigger the tire, the slower the engine turns at the same speed which means the engine can't put out enough power due to the rpms being too low.
The bad news is it'll cost anywhere from $1100-1400 to regear both axles, which includes all parts & labor. The good news is that regearing will actually fix the lack of power problem very dramatically... it's a good fix that man of us here have done. I have regeared my axles twice over the years as my tires got bigger.
The correct axle ratio to regear to depends entirely on your transmission type... manual transmission or automatic. If you have the 3-speed automatic which is the auto that came in the 2002 TJ, you need to regear to 4.56. If you have the 5-speed manual transmission, 4.88 is the correct axle ratio.