I'm somewhat of a beginner to working on cars. I've mostly just done break and caliper work on my cars as well as a few other smaller repairs, but I'm considering taking a shot replacing the exhaust system.  I'm curious about any tips or suggestions that folks here might have or if you think I'd be better having someone else do it.  I've seen some videos online, but I've not seen my exact model replaced.  I have a single tailpipe but it looks like many of the others have two.  I probably could put a dual in mine but not sure if that would even be something to consider.  Just thought I'd ask here...thanks in advance for any tips you all might have. 

Why - are you doing aftermarket or replacing rusty stuff?  

Rusty stuff is waaaaaay more work.  Cutting off rusty fasteners is a half day...or one week...affair if you don't have good tools or experience with rusty bolts and stripped manifold nuts/studs in the head.   

Or it's really easy if it's rusty free and comes right off. If you're doing the entire exhaust it's rather simple because you just remove the 6 14 mm head to exhaust nuts, a supporting bolt or two in the middle bracket and use soapy water liberally on the exhaust hangers and they pop right out and the whole thing drops to the ground. 

After that bolt up your new stuff and you're done. 

Aftermarket often causes check engine lights immediately or later so if you live in an area requiring emissions or the check engine light to be off for inspections then aftermarket isn't always a good fit. 

In general exhaust isn't a good DIY for first timers - but if it's all clean and relatively rust free and you're doing this for novelty/looks/sound, then it can be easy.  

Also keep in mind Subaru isn't as well supported as other manufacturers so the parts fitment isn't as always clear cut and obvious.