You are taking this to a far higher level than most even comprehend. I have been messing with this stuff for decades and made some pretty fast cars that were lame to begin with and you make me have to think, something I prefer to do less of as I get older....
For what you are after coilovers are probably the way to go, As noted you will have to stiffen up the upper mounts, not a bad idea to have a cross brace which can be aluminum to save weight, and stiffen he lower arms and mounts.
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I am back to playing with a FWD, twist beam rear axle, I have had great results with them and kind of fun to beat up on AWD and FWD cars at times with an inferior platform but in the end, a well setup RWD is dang hard to beat when well done, if possible!