Lot 166376: 2009 Cadillac CTS-V

The 2009 CTS-V’s Eaton LSA supercharger has one big sore spot: the factory spring-loaded isolator coupler inside the snout. Over time the isolator’s internals wear grooves into the supercharger shaft, which lets the coupler rattle at idle—usually disappearing as soon as you blip the throttle. GM acknowledged the issue with bulletin 15-06-01-003 and dealers replaced quite a few under warranty. The fix most owners use today is a solid aftermarket isolator (no springs), which cures the rattle and prevents the shaft-seal damage that can come from the metal debris. Because the car you’re looking at already has 108k miles, it’s worth asking the seller whether the isolator—or the whole blower—has been serviced; that’s exactly why “Has the supercharger been replaced?” shows up in the FAQ on its listing. If it hasn’t been done, budget a few hundred dollars for the part and a couple hours of labor (or an Eaton-authorized rebuild if the unit is already noisy). Want me to pull up similar CTS-Vs or dig into anything else?