I have 1600 miles on my car. No oil change yet. No full throttle until 100 miles, and didn't do any racing until 1000 mile mark (although I did a couple freeway pulls).
My oil was too dark by 750 easy miles in first 2 months, so I changed it. I'm now at 3750 miles & the oil is darkening. Since it's now been the 6 months specified in the manual (but only 3000 more miles), it's time for my '13 Shelby's second oil change.
Replace the factory air filter when it starts to look discolored with an oilless type. Don't delay adding a passenger side oil seperator in-line with the engine blow-by PCV.
The factory Goodyears are downright dangerous on these cars & should be upgraded ASAP.
There are many threads on these subjects, but the "2013 GT500 FAQ's" thread by Devious_Snake is the best synopsis to read in detail.