Basically, you can use the 1G battery tray for PC925 batteries but it takes a minor adjustment. As with the DSM, you'll have to ditch your charcoal canister for this.
The firewall bolt pattern is perfect and fitment with the subframe is also fine. The problem is that there's no fender side threaded hole for the second attachment point. I first tried to fix this by installing a t-nut in the fender well but I quickly discovered a slew of support baffles in there and bailed on the attempt.
The solution is to make a small strap to run up to the threaded hole on the strut tower. Just be sure to counter-sink the holes in the strap so that it sits flush against the fender well.
Alternatively, and I'm only thinking of this as I type, you could make a brace that goes between the subframe and the frame-rail and wraps up and around to give you the needed attachment point. If I ever take the subframe out again (I don't know why) I'll give that go. But for now I think this solution is fine. The battery is held firmly in place and it's far cleaner than a trunk installation, IMHO.
You'll also want to take a file to the tray 'cause it comes pretty rough from JMF. It's pretty simple and when it's all said and done you get a battery location that looks like this.