The CTS-V is one of those cars on my short list when it comes to under rated performance cars. however No-one makes decent shocks for them. The only Real Shocks I found are the Koni based KW suspension or K-sport and then only if you buy their coilover setup.. That's the biggest problem I've had with every GM car I've autocrossed. they are just so afraid of a rough ride they never put enough shock in them. Grip will always make you faster, but the true dynamics of the car need some damping.. in that case a $800-$1200 investment will make a huge difference. it's a shame you already bought springs. oh and coilovers also eliminate the problematic at best self leveling suspension.