I went through this myself the hard way, owned both... I ordered in a eco ppack soon as they came out. I thought it would be a great road trip car, it was, but... sold it 2 months after i got it, after a nice 4000 mile road trip, loved the look and handling of the car, gas mileage was great! But...
Beauty! I ordered that same colour combo only did the eco pp. Had the first red 15 in my area as i ordered it soon as they came out, got stopped by police for drug running check on first roadtrip! Police did double take when found out a cheap mustang, as they said they were stopping exotic...
The more weight i get in the trunk, the less tail happy it is.
No doubt you could overdo it, but i never have..Car is always front heavy and bites good on the corners, I rely on the loose back end to get me around corners when its needed.
Mine is flawless, drove the bag off it from the get go, first car ever I will leave the factory shifter stock! Love it! Just trying to find a white hurst type shift knob thats normal hurst (2" or less) size, not the baseballs that I keep finding! :)
My cruise and speedo all match gps, however when i use the digital speed on the diagnostic screen its reads 12 km(1mph) lower..I guess I go buy a camaro!
Just get real quality snow tires on all fours,(nice to be able to stop) not that cheap crap, and dont even try with the pirellis thats on it,i tried... and a bunch of weight it the back (at least 200lbs)I fill up the spare tire hole w sandbags on mine. and you can go most anywhere you will...