I bet you could get pretty close to 19-20k if you find a '13 GTI still on the lot. '14s here start at 22.5 and go up to 31.Also I don't believe you can get a new GTI for $19000. Of course with their faulty engine they may be heavily discounting them.
I have a 2011 GTI which cost $29,000 and even though my ST won't be in for another week or two, I am really curious to compare them performance wise.
I have both the cars in my driveway right now and I'd say that the GTI seems to pull harder while the ST is much more agile. The weight difference is extremely noticeable. The GTI also cooks its brakes faster on the same foothill roads that I wring them out on.
The interior is superior on the GTI, but the seats are better on the ST. I prefer the shifter on the ST, but my wife prefers the GTI. Steering I'd give to the ST. The dog definitely prefers the GTI due to a flatter cargo area, higher roofline, and easier access to the rear windows.
Both are good cars, it's really a matter of preference thing.