[vtirocz]

The key takeaway from all this to me is that the suspension system / tire / aero needs to be tuned as a whole to be optimized. You can't just slap on stiff springs or sticky tires and call it a day. I wouldn't be surprised to see a car with lowering springs alone and stock shocks to be slower on the track than the stock car. The ZL1 1LE suspension kit clearly needs the ZL1 1LE spec wheel/tire combo (and probably aero too) to perform well. This is where GM is at a huge advantage compared to most aftermarket companies - they have the engineering resources and budget to really optimize the performance of the suspension kits they are offering. There's exceptions, but most aftermarket companies probably never have their lowering springs or coilovers on track before launching the product for sale.

If GM advertised these lap time improvements with their suspension kit (on the "build and price" website), I think more people would check the box for that option.