I am running a 05-09 Magnaflow LGT Sedan cat-back on my '09 Outback XT. My excessive research here, the Outback board, and NASIOC all told me I could do two things: cut the tips off and dump them (like the above poster) or cut holes in my bumper cover. I really like the look of straight out the back tips plus it's going with my Mach 3 theme, so I went the cut route. Unfortunately I don't think anyone has done it because as soon as the plastic was rough cut and gone, the crash bar was right in the way. I saw no mention of this in my research (however it was mentioned in JDM/AUS/EURO OB bumper swaps). This lead to hacking it up to make it driveable and eventually bumper removal for final clean crash bar and bumper cover trimming/cuts.
LGT sedan bumpers (and therefore exhaust) is shorter in the tip area compared to LGT wagons or our Outbacks, so extended tips are needed. I'm still picking out new tips and plan on adding a resonator in the mid-pipe to make it more livable (thanks wagons! lol). Also note: axle-back tubing gets mighty close to the driver's lower control arm at full droop and the passenger side of the sway bar at ride height. This may be different depending on your particular brand choice and tubing size. I'm solving that by slightly longer exhaust rubbers.
Some pics and unfortunately my system isn't quite done yet but will be covered in my future build thread.