I've got a '13 Gt500 and an '87 GN (well, actually the wife's). With a few very minimal mods the '13/'14's will easily run 10 sec et's in the mid 130's with a sticky tire. When I say minimal, I'm talking an intake tube, throttle body, underdrive pulley and a tune. All can be had for about $2k or better if you shop around. The wifes car should potentially be capable of upper 10 sec et's and will get the Shelby from a dig but start getting up in the mph and the GT500 will easily walk it. I've been able to beat stock Z06's and keep up with some high end Porsche's and beat others all for less money than the above mentioned.
There have been bone stock GT500's on stock tires running 11.2's & 11.3's @ 128+mph. I will admit a worked over GN will surely be quicker from light to light but go for more than a light and see what the outcome will be. The Shelby's are very traction limited with stock tires and very tricky to launch well. I've been able to pull a 4.1 0-60 on stock tires without heating them up (tests claim 3.5).
My car, bone stock, put down 609rwhp with a 5yr/60,000 mile warranty. You have to admit that's pretty damn impressive for a stock car. With the above mentioned mods the car will easily put down 700+ rwhp on pump 91 gas, no meth or any other additives. While I love the GN it is more of a one trick pony when compared to my Shelby. Trust me, I love to go fast in a straight line (own a 9 sec Fox) but to have a car that is capable of keeping up with some exotics thru the curves, a lot of them on the straights and all for less money is very appealing! I would seriously hope that your mid 10 sec GN should be able to whoop most Shelby's light to light but run into one that's been modded with a good driver don't be too surprised if the outcome is different.
BTW, the Shelby has a Tremac TR-6060 trans with a dual disc clutch. Driver makes a huge difference on how well the trans performs.