I agree with Dyoung...nothing better go in the intake. The thing you're thinking of is AutoRx which you add to the oil 2 treatment and two rinse cycles with any conventional motor oil. As far as the C6, man they are pretty well unbreakable as long as you don't be an idiot like I was and run constant vacuum to it. If you ever mess with the modulator at the back of the tranny make sure it is the correct one and has the pin inserted, otherwise disaster will follow. You need to make sure the VRV on the IP is correctly adjusted and functional. Beyond the correct amount of vacuum don't run it out of ATF and add auxillary cooling if you're towing or hauling extremely heavy, otherwise it's a hop in and don't worry about it trans. Good luck,
JD