In the US, 2.5 is on 348 for 1989, and I'm sure a few others too. You cannot do self-diagnostics and there is only one idle speed motor (if I remember correctly) so the two inlets to the intake plenum appear to have different equipment. The biggest difference IMO is self diagnostic capability. Upgradeable? Sure. Cost prohibitive? Certainly. Worth it? No. Best regards, Rob Schermerhorn
It is not worth the change from 2.5 to 2.7 but the 2.7 definately makes more horsepower. In fact the latest interation of the 2.7 in the spyder produced the most power. People with early 2.7 can just swap ecu's for extra factory power. Some say superchips will do the same thing with a chip upgrade but a Jim Conforti once on this board has reasons to be skeptical as he is a designer of such things. When you add the latest 2.7 motronic and the challenge race exhaust you got the best the factory system can offer.
