Fast driver > fast car, just go for it!
Go gear have been helpful to me in the past so definitely worth a call. I also know of LF performance, Heath Ledger's dad runs it (so I've heard) and their work is top class. They can do fabrication work ie roll cage.
A Forester might have slightly higher centre of gravity due to chassis compared to wrx, but no matter, just keep the heavy shit mounted as low as practically possible.
Seat time on track is worth more than a little power/CoG. Just do it
using the Perth-WRX mobile app