Good luck with that. Ra and lgt gears and even newer wrx gears are the same strength and slightly cheaper. Built my Lgt gears in my swapped rs (2700 ish lbs so doesn't have to lug around as much weight aka less stress) and just about lost third. Lucky for me it's still drivable till I find an sti trans I like. I put down 319whp and 343 wtq at 20 lbs. I got a retune on the street by the same tuner to 23lbs so I got a little more power out of it. I daily drive it and might rip on it here or there on the highway and only launched the 2.5 swap once a while ago. What it boils down to if you're putting out some decent tq even if you baby it you can still lose a gear.
PPG's to me are over rated. I've known a few that have had issues. One the input shaft snapped on a set up very similar to mine. Another person I met recently had an issue with hers with 5k miles and had to send it back to Andrew Tech. There is one for sale right now on nasioc with one broken tooth on second and have come across plenty with less power then then claim they can handle with broken stuff.
Fast forward to why I'm going 6 speed. For one it's a six speed and a couple exrra mpg's does sound nice along with the shorter gearing. In my 10 plus years being in the Subaru game I have not had one person tell me that they blew a gear in the 6 speed. To me that means something. Plus the sti box is a far better design then the 5 speed split case. Just my thoughts and experiences.