hi, i was wondering if a diamond coilpack off a 95 impreza would fit the 2.2l engine ej22 in my 98 legacy gt?? Thanks

Depends on if you have the male end pack or the female end pack.

 

 

They do not interchange easily.

its a female one.. looks exactly like the one i got on my subby

Always wanted to know what was the reason for the change?

The male end packs apparently have higher output. Subaru may have wanted some extra oomph in the ignition systems for the higher compression motors. It takes more energy to bridge the gap in a spark plug when the compression goes up. There are two ways around that, either A: close the plug gap, (which means you have a less efficient spark. It creates a smaller initial flame which takes longer to burn through the entire fuel/air mixture) It also creates localized hot spots on the plug which causes it to wear faster.

Or B: Up the power of the spark, by creating higher discharge voltage in the coil.