So who are the individuals who are responsible for the current GT engine rules ? what does everyone think of these rules ? 5 port with 7 mm insert .... what was the purpose of these rules and did the rule achieve the desired purpose ? I have my own opinions of these rules that I will share later, but for now I want to find out who made up these rules and if anyone thinks these rules were effective and beneficial to GT racing or possibly feel these rules were arbitrary , ineffective and detracting from GT racing.... FYI a 7 mm insert can reduce engine output by as much as 20% and increase internal wear and tear...