We're going to have to agree to disagree here. I've designed suspensions in FSAE competitions, MII is not inherently better. Sorry, it's just not. They ALL have advantages and drawbacks, and coil overs are no different.
Now, you can totally convince me that with the aftermarket parts available for the torsion bar system that you might not be able to tune your car to get it to compete at that level. I'll absolutely believe that, there's just too many coil over options available, and by comparison the aftermarket support for torsion bars systems blows. That I understand.
And no convincing is necessary to convince me that the leaf spring rear suspension needs help, I totally see how a 4 link system is better for this. Which also brings me to, did you convert your entire car to RMS at the same time?