i just bought a 98 outback.is there anything i should know

It would help if u told us the mileage on the car, but the automatics on those cars r pretty much toast after about 200k ifthey have not been seviced properly. Our local tranny shop says they r not rebuilable & a new one from Subie is like $3000. The manual tranny lasts like forever. Again depending on mileage, the head gaskets tend to leak on the 2.5 DOHC, but that is not a terribly expensive repair.

On balance, they're good vehicles & r great in the snow!! Mid 20 is for mileage for an AWD, is pretty good.

A couple of pointers from someone who is owned one: The 96-2001 Legacies were prone to headgasket failures.. this was due to a poorly designed gasket; the engines themselves r a modified aircraft design, & as such.. very reliable. If there is any sign of overheating, shut it off ASAP.
The automatic transmissions, in particular the 4EAT, do not like to be neglected or abused; change the fluid religiously every 30K miles & u will be fine. Manual transmission cars, r very tough by comparison, & the only thing to look for is slop in the shifter, or trouble going into gear. This is usually caused by worn pivot bushings on the shifter itself, & was the first repair l had to make to my own car. We have regular customers at my work who have Legacies with well over 300K miles on them, & no major ills to speak of; my own was severely abused ( hard driving, off roading.. mud, sand, snow).. & it still lasted 155K miles before giving out. l liked it so much, l bought another. IMPO, very tough cars..just do the maintenance, & u will be happy for years to come.

Know that it will last you a VERY long time, easily 250,000 miles if it was taken care of.