I'm currently swapping a new engine in my 97 Impreza. The engine I got for it was out of a same year legacy and I notice the timing belt tensioner is different. Out of curiosity can the tensioner types interchange or can they only be used on one of the other? I tried giving it a search but didn't see much about them. TIA 

I think you need the small bracket with the newer style to adapt to the older.  Give it a good look over. 

And there will be no alignment issues. If you had concerns. 

Edited June 25, 20214 yr by moosens

Yes the bracket that bolts to the engine and the tensioner are a matched set.  You can swap them out as long as you have both.

I have spares of both types if you need them.

yes  swap the brackets they bolt too   Look closely it’s easy to overlook and think it’s part of the engine. 

Compare the hydraulic seal - use the one that’s the most dry.  That indicates the seal is leaking. 

I’d use the older two piece style one if the hydraulic seal is dry.  They’re more reliable, the pulleys can be easily bought to get a new one.’although they are generally older. I’d get like an NSK or OEM brand if you do replace any pulleys.

97 are both interference engines - I’d use the old style tensioner, get a new Subaru belt and new lower clogged (toothed) pulley from Subaru or OEM brand.  Those are by far the most likely parts to fail. 

Although most 97s come with new style tensioners so the tensioner or engine may not be original to the legacy they came out of. 

may not be a 97 engine that you got out of that legacy.  It may have been swapped for a 96 at some point which is more likely to have an old style tensioner.

In which case it may not be an interference engine.  Almost all EJ22s (in stock form) with the older style two piece tensioner are non interference.