I'm new to Yaris. Noisy hwy ride. Is it normal?

[jack black]

I just got 2007 red Yaris hatchback base AT under 66,000 miles with clean title and overall good condition (as far as I can determine). I didn't notice anything abnormal on test drive, normal/fresh looking fluids, and no engine/tranny codes, etc. However, the hwy ride is too noisy for my comfort at speeds 60-70 mph. Much noisier than lets say Corolla, although noise in Corolla was mostly engine and Yaris is not exactly engine, but rather a rumbling drivetrain or tire noise. I guess it could be tires.

Other than rotating tires, anything else I need to worry about?

One more thing. The engine idling noise is normal except for faint knocking on hot engine immediately after a 150 mile hwy trip. I did not hear it on a test drive when car was not fully warmed up.

Am I paranoid (again) or is this the typical buyer remorse kicking in?