Hi.. Just replaced my sons 91 civic si with a JDM from Toronto. Same everything with a couple of exceptions...notably the exhaust manifold is a dual port (at the collector end). I know the CRX and Si/ DX motors all about the same, But I wasn't aware of the dual manifold. My daughters CRX had a single exit. Anyone know if that is common here in North America, or maybe just a Pacific rim item. Would make for a niffty exhaust system if useable. Will put it up for sale, as I had to use the original manifold from the dead engine. Thanx for any info Ray