I am definitely feeling like the car is down on power and seems to take longer to build boost. I have no dyno numbers or 1/4 mile runs to back this up, but the butt dyno is telling me I have an issue. I had lost almost 3 miles to the gallon about a month ago and it turned out to be bad 02 sensors and and older spark plugs. Changed them out a couple of weeks ago and I am back to getting what I was accustomed to in mixed driving, approximately 14 mpg. The car is definitely not pulling as hard or as quickly as it used to and the next thing I would like to check is if it's a belt slip issue. I have a smaller pulley and accessory tensioner, but I don't know how old the belt is and thought maybe that could be the issue.