Judging by what's been going lately, $10K to $12K would be my guess.
Worth more, but no one has been paying more.
It's 12 years old, so with only 19 thou on the clock it's been sitting around waaaaay too much.
The farkles don't add a cent, but are definitely attractive.
Make up a list of ST13s on the internet sales sites (year, ODO and price) and see where yours fits.