I'm likely going to order a Toto Vespin II today and need to order a toilet seat to go with it. I saw a post recommending the SS164 seat but I only see a SS154 available for order. Are these the same seats (different shapes, perhaps?).

I'm thinking perhaps the SS164 was a typo.

Also, what's the difference in the SS154 and the SS114? Is it just the molding around the cover or is the seat itself different?

Toto's website is remarkably unhelpful in this instance.