The pipes from the exhaust manifold are no longer there, the DPFE sensor is gone, the egr valve and solenoid are gone too and there is a simple blanking plate over where the egr enters the uim. Plus they deleted it from the
ecu.
A simple blanking plate over the holes to the uim will keep your manifolds in a much healthier state. The car will throw a code (for restricted egr flow) but is no issue cos there's no check engine light on the ST24.
An essential mod on our engines imho.
I blanked mine when I fitted the st200 (SVT) manifolds about a year ago and don't regret it for a second.