Coilovers for late model 911's

I am going to be upgrading an 87 911 from stock to track car. Since I have to redue the entire suspension, (T-bars, shocks, bushings, sway bars, Adjustable springs plates), I am looking into Coilover kits for these cars. So far, I have located one vendor that can do this for about $3000 less sway bars. Does anyone have experience with a car that has been changed over to coilovers? I realize that some structural support is needed at the rear shock mounts behind the engine. What companies are producing coilovers today? Windward uses Bilstein RSR struts with Eibach springs. The spring rates are easily changed for performance along with ride height, (the beauty of coilovers). What I want to know is does it improve handling over the T-bar/shock setup? 23mm - 31mm would be the size for the torsion bars if I went that way.

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