I don't believe that Toto was bringing in the 3" flush valve models 10 years ago. If you have the "water churning" model, I'm thinking CST703 with the "washdown" bowl. That models retails at $130 and is sometimes discounted.
If there is something stuck in the trapway, performance will go down.
The top performers are the 3" flushvalve Toto models with the siphon jet. These are the best I've seen.
The 3" flush valve is 2.25 times bigger than the old 2".
Simple math will tell you it's a new kind of animal.