The only internal strength difference I am aware of is the change to cast pistons in '00. The crank and rods are still the same forged units to the best of my knowledge.
Question at hand is whether it is better to get a newer model with the misc improvements that were made along the way (like anit-lock brakes) knowing you'll need to swap pistons if you decide to run a blower with more than about 6PSI or want to go crazy with nitrous or go with the older model so you don't have to worry about the pistons, but give up some of the improvements.
--- Ken