Ive read that the best rear suspension is a long torque arm three link suspension. they are run on lots of fast race cars. THat bieng said I run a leaf spring rear with shely tracion bars. the bars bind a bit and lead to oversteer but I am going to remedy taht soon by replacing the rubber bushings with heim joints. I run heavy 5 leafs and get great tracion and good contollable grip. I would run a leaf spring suspension over a 4 link, as tehy are better for road racing.