I'm not limited by the PPF, as Ive already moved to a Banzai trans and Sikky diff brace on the stock diff, as well as bushings. I don't weld (and that kind of work around here is expensive), already have the car corner balanced (which you'd screw up if you dropped the subframe), and I wouldn't want and a locker diff. I get what you're saying, but for me, I'd rather go the casing route if it were available even if it was a bit more money.

It's just potentially simpler, and allows you to upgrade sequentially rather than going all stock to a whole new setup. I only did the Sikky for weight, as Ive never had an issue with the diff or the PPF, and the only reason I foresee needing a new diff is for the ratio really.

How much power are you making?

The limit of a braced (which is separate from the Sikky diff *mount*) stock diff with a silky mount, with or without the PPF installed) is ~550whp. I would give this article a read:

https://motoiq.com/project-fd-rx7-re...-differential/

A Traction-Lok is a clutch type LSD, not a locker.

If you're not mechanically inclined to remove diff housings or subframes, then learning how to weld probably is a significant hurdle. If you can do that work, watching a few YouTube videos and practicing on some material will enable you to weld the brace in. It's really not that bad if you don't know anyone who has ever MIG welded anything.

If you want cheap gear ratio options, the Ronin kit is still your least expensive option. IMO. Pulling the trans is more difficult than the subframe.