Waldo

The blow off valve is all about noise, it will offer no performance. The K&N intakes are all about letting more dirt get into your turbos and ruining them faster, it will offer virtually no performance.

If you want opinions, then mine is that you've waster hundreds maybe thousands of dollars in you past cars with the 89. Any modern car will run just fine on 87 unless it specifically says Premium required, in which case you need to go to 91 or higher. 89 is really only useful in older cars that have problems that would cause knocking.

Enterprise owns hundreds of Fusions of the same color. Chances are the trunk on yours got damaged at some point and they had another car sitting around with the same color trunk but maybe some other problem like a broken windshield so they just switched it to keep one car on the road and available to rent out.

Could be something has gone bad in an engine mount that causes the powertrain to roll over and contact the body during the turns.