I owned a 1997 Outback until recently ... virtually identical to the 99OBs. Never towed much with it, but it's OK as long as you are aware of it's limitations. Assuming your car has the same specs as here in the U.S., towing limit is 2,000 lbs with trailer brakes
and 1,000 lbs without.
The thing to watch for on the 96-99 Outbacks is the cooling system and headgaskets. The cooling system is OK under normal conditions, but you really need to have the system in tiptop shape, i.e. fresh coolant, clean radiator, no leaking hoses, and a radiator cap that's not an antique. One piece of good news is that the Subaru waterpump and thermostat are near bulletproof. If you ever need to have those items replaced, be sure to use genuine Subaru parts.
The 2.5L DOHC engine is known to have head gasket problems. If your head gaskets have already been replaced by a quality mechanic, you're probably good to go. If you still have the factory original gaskets, it's probably only a matter of time.
Other things to consider, if not done recently, and assuming your car has an automatic transmission:
- Service the transmission and get some new fluid in there. A simple drain-and-fill is sufficient and better than a "flush".
- Replace the gear oil in both the front and rear differentials.
- I strongly recommend adding a transmission cooler, especially if you're towing in the mountains. Heat is the enemy of transmissions.
- Make sure the brakes
are in tiptop shape with reasonably new brake fluid.
If you have a manual transmission, only the rear differential needs service as the front one shares gear oil with the transmission.
If you have any Subaru specific questions, head over to SubaruOutback.org. I've been a member there for 5 years and it's a really good source of info for all things Outback. Lots of DIY info if you or a family member are into that.
BTW, when I sold my 97OB, it was because I bought a 2014 Outback 3.6R for towing my Campstar trailer purchased last Spring. Love the car and hope to get it and the trailer out on the road soon.