I have a 06' WRX Wagon. I am thinking about upgrading to an STi Helical LSD further down the line. Does anyone have any experience with this set up? I don't want the full on 6-speed tranny, just the diff in the stock 5-speed. I would like to hear what kind of experiences/problems people have had. Also, approx. how much should the install cost if done right? Any help is always appreciated.

There's a guy on here with an '05 wagon running an STI front dif. I think he's had good luck with it. May I ask why you want to get the front diff?

What do you mean by STi diff? The diff from US STi, a diff from JDM 5spd pre-GDB STi or STi optional diff?

Good question about the front diff. I assume it would be the helical unit found in the 05+ US Sti. However, I don't really know the details, or what really fits. As for why I am considering it, I like the way they handle power in cornering. My old GS-R had one and it made a big difference. I am wondering if it makes that much difference in a AWD.

I bought an older, but brand new, STi 1.5 clutch-type front LSD for my '04 wagon.

At the time, I was autocrossing, but the addition of the unit would place me in a different class. I've had it out at the track just once since its installation, but frankly, I can't tell you what, if any, difference it made. However, that's probably due to the fact that I was paying more attention to my driving, and that I'm still a very rookie driver, thus not really able to notice the "feel" of the new unit on a dry track. Also, the installation cost was fairly steep.

I think Sti's now come with the helical units, similar to Quaife, but there were some proponents in the Forums who thought that even though the helical units might last longer, they were not as good for a couple of reasons that escape me at the moment.

If I were you, I'd just spend the money on other suspension upgrades (springs, struts, tires, rear swaybar & endlinks) and driver improvement (i.e. tracktime).

Thanks for the advise. I think I was just missing the feel of my old Integra. Nothing worse than spending a years salary on your ride, getting it dialed in, and having it stolen before you even got to say goodbye. It did help get me into the wonderful world of WRXs, though.