This and a cat-back HKS exhaust are the only performance mods on my car, and tuned on 95ron fuel at the moment. They are not for sale new anymore, but I have seen them for sale a few times. However, I'm sure there are newer, more adjustable options these days which would be easier to get hold of and get tuned.
Thanks for the comments - the bodywork paint is great, and interior is pretty good also. Not really happy with the black paint on the window trims etc, but one day.. one day..