It's all a bit of a guess at this point. Might be a good idea to upgrade my intercooler hoses to silicone too in case 19psi is enough for them to collapse a bit.I know Jak Stoll used to talk a lot about waste gates being blown open under too much boost. The c900 guys were using helper springs and such to cure the problem... not sure that would be the issue at only 18-19 PSI?