Yup.. Its common with a DP, FMIC, Sticky tires, to go 12 flat to high 11's on sticky tires in the EBM. Tune+ is a great tunner. He's got a slew of cars on stock turbo's doing 11's all day long. I'm using him for my car as well. Also don't assume the EB mustang is a heavyweight compared to the Focus RS. My base model with a light weight single exhaust came in at 3550 with my lanky 130lb ass in the car and 1/2 a tank of gas. No bells and whistles for the win!
The current full weight stock turbo record is in the 10's using spray and race gas and there is another car that is super gutted that is running faster on the stock turbo with Meth and race gas as well. Also several cars making 500+ HP on big turbos and stock blocks just waiting to toss a rod out the side of the block. Right now the limit is fueling because of the damn DI but Aux fuel systems are being developed all over the place. A lot of them sound like shit with dumped DP's or minimum race mufflers but they fucking move out.
Here is the Mustang 6g ecoboost leaderboard..
Official 1/4 Mile Fast List & Leaderboards (I4 Ecoboost) - 2015+ Mustangs - 2015+ S550 Mustang Forum (GT, GT350, GT500, Mach 1, Ecoboost) - Mustang6G.com
there are a few fast cars not on this list but they don't post on 6g.