I have the original factory tires on my 2005 Prius, Goodyear Integrity. 26000 miles and in desperate need of replacement. I have been thinking of the Goodyear Assurance Comfort Tred. They have good review in Consumer Reports. I am hesitant to replace the original Goodyears with more Goodyears though. Has anyone replaced theirs with the Comfort Treds and if so, I am interested in the best PSI to maintain the MPG.