I don't make the rules as to what pipe is for what engine. I can only tell you what happens every weekend,when I race against this particular truck,anyways. It's not just this truck either. My GO7,with the 2013,has never been pulled hard on a straight,when it was tuned correctly of course. Sooo many factors and I'm not gonna get into it. I was just stating my experience.
Rocket42-If you ever get the chance,give the 2013 a shot on the GO. It had ALOT more low-mid than the 086. I would not call it the "wrong pipe" by a longshot. I can honestly say though,I haven't gotten to try an 053 yet. That's next on the list.