I installed a short shifter in the C30 today, I should have taken more photos but hopefully this will still be helpful.
It was fairly involved and involves some cutting and modification but the result is pretty good.
This will of course be the same for P1 S40 and V50 as well.
I used a kit from a Focus XR5/ST, there is some modification required to use this which you can avoid by getting a proper Volvo one (there is a guy in the US who sometimes offers them as a copy of the old Snabb ones) but they're like $200usd compared to about $60 I paid for the XR5 one on ebay, plus you'll need to get an XR5 one anyway because there is a piece that the Volvo one doesn't include.
Start by removing the waterfall console and centre console trim piece, there are guides online of how to do this. Remove the screws for the main centre console but don't take it out of the car since I found it useful to have in place at times for test fitting etc. Disconnect the shift cable.
Towards the back the shift cable passes through a black plastic thing and this needs to be raised up, otherwise extra stress is placed on the shift cable. The piece to do this is included in the XR5 kit but not the Volvo one, probably because it's not a direct fit. However to achieve this you need to cut out the plastic directly above it.
Remove the blue plastic clip and pull the shift cable out (I did this before the above photo obviously), this is easier to do with the centre console pulled out of the way.
This assembly sat too high, making it so I couldn't reinstall the coin tray. To fix this, I cut a few mm off the bottom of the metal piece, and also cut the top corners off the U-shaped cutout in the yellow plastic:
This makes the cable sit nicely but it still sticks up slightly too high so I tried to cut out a bit of the bottom of the coin tray a bit. You could probably cut all the way through if you want since there is a rubber piece on the other side. Note that you can avoid all this if you don't care about the coin tray.
Now you can install the back part of the shifter cable so it looks like the first picture.
Next is adapting the Focus part which is shorter than the Volvo one. I extended it by using a 25 x 3mm piece of aluminium. This picture is just a trial piece I made but shows the concept. This step can be avoided if you get hold of the proper Volvo kit from the US.
The final one I used was about 60mm long, and I bent it to match the angle of the stock plastic shifter connector below. Because the two holes that secure the aluminium to the main piece are very close, I had to file down the bolt heads. Then connecting the shift cable to the ball is very easy.
I mounted the ball about 10mm further away from the shifter (ie towards the front of the car) than it technically needs to be, this makes it so that the shifter is closer to you in the driving seat. The photo below shows it in 3rd gear, it pretty much looks like how it normally would in neutral. Not sure if I'll keep it like this, but if you don't want it this way, just make the aluminium piece more like 50mm long. It's a bit of a trial and error process.
And this is the finished product:
After that it's just a case of putting it all back together.
I found that the coin tray behind the waterfall console still doesn't fit perfectly but I can live with it.
If I've missed something let me know, I'm sure this thread will get lost but hopefully it'll be useful
