If your stereo has connection to CD changer there should be line in pins which you can use to connect your iPod (any MP3 player). But for this definitely you need a shop.
When I was replacing back struts of my '94 Legacy II I noticed that original ones were KYB.
I have replaced it with Bilstein struts, because of availability and price.
Never seen 91 Legacy dashboard connectors but for my 94 Legacy II I have used plug where it fits "technology" because all conectors has different shape.
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Egidijus
Subaru Legacy II '94
Try to use this info: http://www.geocities.com/kuleshoff/IAC.htm
But I do not know is it correct or not. I have not tried yet.
Egidijus
Subaru Legacy '94