I de-cated my old pug 206 1.4 and it made no differance at all apart from the loud noise... dont know if its true or not but apprantly youl ose power threw loss of back pressure?
 
all that money and effort for maybe a 1/4 mile time of 18.8 instead of 18.9 if you're lucky? Lot of money to compensate for performance loss from 17"s, stick 13"s on if you want performance otherwise stick to the show, not the go ;)