I have an almost new JLT CAIP-GT500-10 cold air intake for 2010-2014 GT500s. This CAI is the one that requires a tune for the car. It is usually advertised for about $350. The 5x7 red oil filter is new in wrapper, the black plastic airbox is new, and the coupler is new. I also have the gasket for the MAF and the two screws that fit into the tube. The tube was used for 10K but is still in very good condition - has a rubbing scratch on bottom...its hard textured plastic. There are also two stainless steel clamps for the coupler. There is no oval foam diffuser. I don't recall getting one with this older unit but they now ship with them. It would go in the front duct intake tube to restrict air flow. You may be able to use the original one from your stock intake. It is an as needed part if your intake is providing too much air and causing idling issues when slowing down. Price is $220 shipped, $200 if you can pick it up in the Kingston, Poughkeepsie,NY area or close by.