3.18 is the gear ratio.
Stock 240's have 3.23's
I switched those out for smaller gears that allow higher speeds in each gear.
(plus I blew up the rear end with too much nitrous)
When we re-assembled it I ordered the gears through a Nissan Motorsports representative at Courtesy Nissan just north of Dallas, Texas.
The 3.18's came stock in several of the other Nissans, and we got our hans on some from a skyline that had been adjusted by Nissan Motorsports to work in a 240.
I run on Yokohama's Drag Radial equivalents the YK420.
At the track I drop the pressure to 27 psi and light them up until 3rd gear in the water.
When I stage, they're as sticky as Micky Thompson E/T Streets, and almost as bald
As for Limited Slip, nope, don't got it.
I do tend to get the one wheel peel on the street, but it's normally not a problem at the track.