I HAD it running on my 00 ej22 impreza.
I recall the hardest part Being getting the virtual COM port to function correctly.
I understand, this being windoze (xp) and all, but I'm leaning away from that being the problem. This has actually been a bit of a saga. The first cable I bought (over the winter) turned out to have the CH340 chip, which I (too late) learned is unsupported. So I ordered up another one, this time making sure to get the FT232. Got it in today's mail (five weeks later...) and confirmed the FTDI part. Downloaded driver from FTDI, installed it, and windoze reports it as running properly. When I fire up FreeSSM and attempt the connection diagnostic, it picks up the COM port properly from windoze (I've tried both COM5 and COM1), then errors on the test. Strikes me that the car controller's physical layer shouldn't be at fault, since my little Autel OBD2 code reader can scan through it just fine.
I'm hoping someone around here will say "you bet, works fine for me" and won't mind my popping over for a visit with the car, laptop, and cable. If that happens, we should be able to suss out in about two minutes what the hell is going on here.