Well the complete LBZ setup is best as GM even had a TSB to install them on LLY back then. The K&N is not good all around as there is better options available. I do not think K&N ever made a turbo mouthpiece where the problem is with the factory setup. Look at the turbo mouthpiece closely and maybe even take a pic.Do you recommend that just because the LBZ is known to be good, or are the K&N aftermarket kits known to be bad for LLY? This K&N looks to have been professionally installed... it's the entire intake system including mouthpiece, not just a replacement filter. The kits are in the $350 range when new so I hate to scrap it, unless we know it's not as good as the LBZ option. Several have mentioned to ditch the oiled filter and put a paper cone filter on, since they run just as clean and won't send oil into the MAF sensor... so I do plan to do that (if I keep it).