rear suspension choices

car is a 70 duster.. going to be a handling car ie roadrace autcross.... with some drag time.. car is underconstruction so i am open to any suspension... my question is wich rear suspension would be better for handling....
im debating between leaf springs or a 4 link

the ones that caught my intrest is reilies street lynx, and i also liked the road race leafs from firm feel...

to clear up ?'s on the front i am going to still use the torsion bars and will most likely use firm feel components (bars, a-arms, sway bars)

wich 1 would be better i want to use the 1.18 bars and match the spring rates for the rears