Pretty much everything is different. Everything is softer, more damp (exceptions exist) more responsive, better built (exceptions exist), and lighter. Fiberglass has progressed, resins are better, core profiling is more exact and more understood. Rocker.
Boards are made of natural materials. If you bought something from 2000 and literally never rode it today it would ride like poo. Board materials break down over time regardless of how often its been ridden. A 2005 that has been ridden at least 60 days is surely smooshy and dead.
Get something new.
Go ahead, drink that kool-aid.
FS: Forum Sauce 142 $200 plus shipping
FS: Flux SE30 $75 plus shipping