The hotshots will work with the VQ30 as well. There are many 5th gens that have them. I think you have to relocate an O2 sensor or two, but with a modification like this you have to be willing to make other small changes. I also think the Hotshots have an EGR bung as well, which if you have a Cali-spec will have to be welded shut because we dont have EGR's.
The reason you wont feel much from the install of a y-pipe on a cali-spec is because not all of the pre-cats are removed like on the fed-spec. When you get headers all of the precats/ restriction are removed.
I will hopefully be installing the Cattman G2's this summer! Keep your fingers crossed for me
