Originally Posted by 80's old school
Do you have the GSL or the GSL-SE rear? There is a huge difference.
Not really. The -SE rearend has different axles in it, and a different gear ratio, and fewer clutches in the diff, but they're the same unit. I have a GSL-SE rearend with 12A axles in my car right now. (I really miss the 12A diff)
Now, Series 1/2 and Series 3 have a huge difference... the axles and axle bearings are larger in Series 3 and the differentials necessarily have different side gears to take the larger axles. You can't switch axles between the two different bearing sizes.
Strength-wise, you won't be able to get enough tire under the car to hurt the rear, so don't worry about it. Rice Racing regularly put near 600hp through one and he just changed axles every 20,000 km as preventative maintenance. (I suspect Moser axles would eliminate this concern)
I did split a housing but that turned out to have been due to collateral damage from a sideswipe collision - the Watts link bracket made a crack and the crack propagated over time. Solution - don't get sideswiped
and run a Panhard or just brace the Watts to not be in single-shear.