While the 5mt case is probably not the main issue in seemingly high failure rates, the aging case design does seem to be a contributing factor. In regards to weak points, I've highlighted some areas that could be suspect.
My products will address these weak points by fastening a large 1/4" thick steel plate into all major front and rear transmission bulkhead bolts. Bolts with a higher-than-factory rating will be included and will allow for a marginal increase in bolt torque specs and huge increase in fastener rigidity to clamp everything together a bit tighter than possible with the factory bolts. There will also be an additional tubular front diff housing brace available. These parts are being released under the brand name "Nighthawk Automotive Engineering."
1/4" Steel plate, class 10.9 bolts featuring 130,000psi yield strength in 8mm and 10mm diameters. Solid steel rod on the diff brace.
Reinforcement Plate: 2002-and up WRX. Diff brace: 2002-2005 WRX (looking into compatibility with 2006+)
All applications from stock to heavily modified. These would be good products for additional bracing on a stock transmission, and they would be great foundational/supporting mods to compliment an aftermarket gearset install.
Initial production runs of 5-10 units per week, though this could probably be increased quickly if there is enough demand.
Final design complete for reinforcement plate, 1st production run of 5 units complete.
-Working with a Nasioc vendor on a distribution plan
-All materials and hardware have been sourced for small-scale production.
-Planning on new affordable shift bushing designs released under Nighthawk name in solid aluminum or brass and possibly roller bearing forms for competitive driving applications.
I want to make it clear that this product is probably not going to single handedly allow you to beat on your transmission like a rabid gorilla without breakage. The idea here is to strengthen some weak points of the 5mt's case design. It's always good to use stronger hardware and reinforce obvious weak points to make the transmission more durable as a whole, and this will likely be most beneficial when complimenting any "upgrade" gearset for above-stock power output (LGT, STi 5mt, MFactory, PPG, etc.). I expect the difference to be more noticeable as power levels increase.
Feel free to ask any questions, for more info on these products, visit: http://www.nighthawkautomotive.com
Production Reinforcement Plates:
Production Driver's side diff brace: