yep making these kits seem fun till you try doing it. Why are bike kits more expensive than car kits. Mostly because they can be. base car kits are pretty cut and dry. They all use a variation of the same turbo and the headers are pretty much cookie cutters because of the large amount of space available as compared to a motorcycle. Mass production drives prices down. Point blank. Also the less competition the higher the markup.
I helped put a C.F. Neon kit on. It was bone simple but I haven't seen a finished product as of yet.