Gearbox Failure Common in Subaru Impreza WRX?

AutoSpeed has a really awesome breakdown of a widely known problem with the Subaru Impreza WRX and Liberty RS: Namely, that the five-speed manual gearbox is prone to failure. They note,

Keenly driven WRX/RSs with engine mods are likely to experience gearbox failure. This is largely due to the immense traction of the Subaru all-wheel-drive system, which (on a dry road) doesn't allow engine torque to be dissipated into wheelspin. Furthermore, those mechanically tweaked Subarus with an aftermarket (ie non-slipping) clutch will trap even larger stresses in the driveline. Without doubt, an up-rated clutch is a big contributing factor to gearbox problems.

They go on to note that the gearbox has a common point of failure; the teeth are stripped from the first and second drive gears. The article poses a few possible reasons for this failure, and suggest an aftermarket product, the Middleton Rally Team’s heavy-duty dog gearset. The only major downside to the MRT gearset is its noise-level, which is somewhat fierce.

Until a helical cut dog box comes along, we'd have to say that the MRT gearset is only for those drivers that like to play on weekends - there's no way you could put up with the noise of a dog box in an everyday vehicle. Motorsport - such as rally, circuit and drag racing - is this product's biggest outlet. Apparently 80% of MRT's present dog box sales are for rally cars - where, obviously, gearbox noise is of no importance.

The whole article is worth a read.