If you are talking trunk, do you have a sedan or hatchback? If you have a sedan, IMHO, it is not worth it to add this brace, as the sedan is already much stiffer than the HB, due to the fact that it does not have a huge hole in the rear. You would probably get more of an improvement from the ITR rear sway bar(MUST be reinforced), or a lower tie bar. These are all things that would probably put you in a different autocross class.