Thanks for measuring!! Hmmm...That is a strange ID size. However, the length could be used for the 200 ft/lbs. spring rate.
The Accord springs are a heavier gauge than the stockers.... the stock Subaru springs are 2.5" i/d.
The stock springs have a slightly larger o/d. I'm sure the Eibach springs would work fine.
P.S., What type of VWs are you into.... I'm an A1 chassis freak. I got the Subaru, because I needed a reliable car! Ironically enough, the Subaru left me stranded today.... I have no clue how to work on this thing.