Not really performance per se but...

I bought a rental 2013 V6 base with 60k+ miles and no complaints.

Really got excited about a car for the first time in many decades.

It had noise in rear end and the ford dealer made these repairs. Sway bar, lower control arms, and some work to the rear end as the driver side was leaking fluid along the outside of the axle. The ECM was reprogrammed to fix the oil life sensor not working.

I changed tires that afternoon from stock 17s to take off 18s.

The butt accelerometer indicates this car runs like a scalded dog now. Gas mileage dropped which is fine, but responsiveness make this seem like a different car.

I did discuss with the dealer the tire change as well as my desire for a 3.31 or so rear gear. I didn't buy one as it would invalidate my warranty. My speedometer is also correct compared to Gps.

Any thoughts other than enjoy and don't look a gift pony in the mouth?

 

only thing I can think of since no mods were done to the car would be the new suspension parts. Even though they are stock replacements, they are new compared to the worn out parts with many miles (since it was a rental, who knows what kind of miles they saw). Also reprogramming the ECM helps sometimes. I notice with my tunes that after a while it seems not as peppy and as soon as a I reprogram the car it is ready to rip down the road.

 

The new bushings will make things feel tighter, but I don't know if it'll make it feel faster.

If your rear was leaking fluid, it's possible that parts weren't properly lubricated before, but are now. The reduced friction will make things faster.

If the wheels or tires are lighter than your 17s, it'll be faster. If the tires are worn and give a smaller diameter than your stocks, it'll accelerate faster but give a little bit worse cruising mpg. (however, if gps says it's accurate, it's probably not this.)