Has anyone one installed one? Their online literature states they use 12 diodes with 300% more surface area to dissipate heat.

Not cheap...

http://www.mechman.com/alternators/dodge/full-size-truck/ram/99-02/5-9-diesel/

I agree on the price. but if they work!

Well even the stock OEM alternators work for half the price. Either way you need to modify your truck for the large alternator (large charge lead, larger fuse, etc.) which now adds more price to the tag. But still in all does it guarantee they alternator is going to lass longer or not have AC noise problems. Maybe? The only reason I would see a oversized do the job better is in this case more diodes to handle the loads but also having enough alternator to cover the load of the grid heaters (maybe) depend on how much RPM's are need to charge at full rate. But still that's going to add quite a bit of parasitic load to the engine as well.

i was thinking of running dual alternators for my winch. warn 16.5k <-- 500A max draw iirc