http://www.toyota-4runner.org/4th-gen-t4rs/162125-coil-rates-oem-4runner-oem-fj-moog-others.html
the coil specs show you'll gain about 1.58" from the coil springs alone IF both were brand new installed using the exact same shock. Anything gained over 1.58" isn't necessarily a "lift" it's just getting you back to where you were when it left the assembly line (overcome years of use/sag), and maybe a potential "lift" caused by upgrading to the 5100's even on the zero setting. Not sure if anyone has compared a 5100 on the 0 setting to a stock shock to see if there are measurement differences from seats to perch and mounting points... etc.
numbers don't lie, so while you may gain 2.5-3" of 'perceived lift' from what was installed previously, it's more likely 1.5-2" from the measurements when it left the factory floor brand new... numbers/specs don't lie, measurements are time dependent especially with suspension components.