Installed a new Kartboy Short Shifter to suit STI MY04-13. NOT Liberty.
This Kartboy Short Shifter replaces the stock shift lever in 2004+ Subaru STI. Overall shift throw is decreased by 40%, providing a noticeable difference and a solid feel. The Shift knob height will also drop 25mm as well. Constructed of CNC'd and TIG welded 4130 Cr-Mo steel. It will install with simple mechanic's tools in under 30 minutes.
^^ That said, with a bit of extra mucking around, it can be installed. And once installed, you'll love it! I sure love it - it's like a completely different driving experience
Comparison pic:

For future reference for those who might install a WRX STI 6 speed shifter into their Liberty, these are the problems you'll encounter.
Holes don't line up. Luckily this bottom piece of plastic isn't too important since it just holds the leather boot up and covers the reverse lock out spring. You have a few options: glue it, screw it, or zip tie it.

The other problem as discussed in another thread was the reverse cable outer needing an extension sleeve. I used a 30 mm sleeve which works well. Could do with a slight adjustment down at the base of the cable, but it's still fully functional!

And here's a few happy snaps from SubiNats show and shine


