The SR20DE engine you will find in the SE (2.0), is a more improved version of itself that has been around for awile. The 1.8 liter engine is all new for 2000 and up XE and GXE's. I've found that the spark plug setup accustomed to the 2.0 is not there for the 1.8. They seem to use a slightly different intake, knowing that someone around here had their cold air intake meant for a 2.0 installed on their 1.8. Other than that, I'm not sure other than actual real technical stuff. Hope that helps man.