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If the person is not interested in actually ripping the car and drag racing sure the stock ls1 driveshaft might be fine.

As for alum. being fine I stand behind my statements that aluminum is for popcans not driveshafts. Al. has no fatigue limit and will eventually fail, even more so with the stock thin junk al. ls1 driveshaft. Each time a force is applied to that aluminum driveshaft it gets weaker and weaker. A better choice would be a mild steel or a chromoly steel driveshaft.
Please back up your claims that an ls1 al. driveshaft will be fine. My guess is you must work in some sort of materials engineering. Or perhaps you received your degree in metallurgy?