I have friends that have a 2013 plug in. There was a mistake where they ended up replacing the Regenerative Break System and then found out the head gasket was blown. They wouldn't have done the break repair if they had known about the other. They have now put $9000 into the car. It also has 2 new front tires. Their last Prius went well over 300K and I have a 2008 that is at 210K. Would this be a good bet at $9K?
IMHO; NO, if you don't wrench on cars and need to pay someone else to do the work. There's also the low tension rings that cause excessive oil burn, that's why people here say to clean out the EGR every 50K-75K miles. The gen3's are problematic, unlike the earlier and later generation Prius, as your friend has found out..
a new regen breaking system (whatever that is, transaxle?) isn't worth much since they rarely wear out or break. here is a comparable for you:2012-prius-plug-in-houston-tx-area.258540
