2014, less than 2k miles. On start up occasionally my RPMs drop and she shutters for a second, then RPM's return to normal idle. Any ideas? If it keeps up, I'm taking her in.

How does the ST run with the catback and downpipe installed without a tune? Also, my dealership said it is going to take a month to get the replacement motor mounts to fix the 1-2 bang. Should I wait to install the exhaust until the mounts get replaced to avoid warranty issues? (I'm worried...