Was just compiling my reply as you posted
Hard copy workshop manuals, other than Subaru's own, are few and far between and AFAIK were only ever produced by US Haynes (and one other company - Chilton?) for a few models.
Yes, Subaru Hard copies were available as I have the MY97 version which ran to 6 volumes and was very expensive.
I'm not certain whether a complete MY98 manual was produced or "supplements" were used to add the MY98/99/00 change information.
From 2000 the manuals were produced on CDs in pdf format, hence most are available on the web.
Even then, the intermediate years between major changes were initially supplement CD's.
From about 2006 onwards the CD's became interactive and were produced in both HTML and pdf format which could linked into Subaru's SSM software
until