If you google ( Subaru legacy trailer hitches ) there are many hits on aftermarket recievers from companies like Curt and Reese ( I have a Reese reciever on my Pontiac Solstice roadster), and tow my TI on a trailer with it (the trailer is a $140 dollar Harbor freight trailer)
The aftermarket recievers for the Legacy over here look to cost between $50 and $100 bucks, It took about an hr to put mine on myself in the garage on my Solstice.
Obviously Pontiac doesn't recommend towing anything with the Solstice (just like the Legacy), but people do anyway.
I don't have a roof to attach any racks to (thus the trailer)
If you end up with just roof racks your might end up looking something like this pic I found
Here is a pick of my reciever T-bar, However I have a way bigger boat, and a whole lot more roof area to work with so take my suggestions like a grain of salt.
just trying to help
FE