All speed runners

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There are some factors to consider such as gearing options, top speed youre trying to reach, and length of road youre going to run on. A 3.3 would be easier on the the electronic components whereas the 2.8 would add more load on the same pinion/spool gearing. But the 2.8 would spin at a slower rotation, so less wear on the drivetrain, possibly. The 1721 takes awhile to get it RPMs up and 3.3 would make it that easier.

Its all very situation dependent
The 3.3 diffs are easily good for 150mph+. If you're not planning on taking it beyond 160-170mph and you have access to the full spectrum of pinion/spool gears, there's really no pressing reason to swap out the diff gearing. Yes, there's the lone factor of lowering the rotational speed of your center driveline that has already been mentioned, but to address that I would first go the route of upgrading your center drive shafts with high quality CF or Ti shafts to eliminate vibrations. And while this is only a superficial/aesthetic benefit of the 3.3 diffs, they do sound cooler than the 2.8 gearing. They have a definite F1 vibe going on. But that's just me.
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