As above a post in the relevant section 8L, 8P ,8V will get you more responses, and I think you will find that there are a lot of people people who have done this. And they will all pretty much tell you that it makes a big difference, especially if you goto someone who knows what they are doing.
Post some details about the car such as the year , and if it has any mods . Also where are you in the country? .
Little point in recommending the best tuner in Cornwall if you are in the Orkneys .