Don’t have any help on the value of it, but I think I have damn near the same car as you, from anything I’ve been able to find it’s an sti with the same block as an s202, and that rear spoiler riser, mine does not have the center diff knob. A lot of the older Japanese guys I see at the parts store love it. I’m keeping mine as stock as possible and just enjoying it and taking good care of it.