Those are nice lookin...what grit paper did you use? I'm assuming multiple grits.
Not sure if anyone mentioned this but the 2007 Impala's didn't come with a 3800, either a 3500 or a 3900, just saying.
You can mod your car with those many miles. My car has 166,500 and i'm still buying parts for it. Runs good too! It's all in how you maintain it.