In what regards? It was touched on earlier, but she needs enough barrel length to keep the velocity at a point so the bullet can do its job. Looking cool do not end critical situations. SRT's mission for the department isn't the same as patrol. Just like bigger isn't always better in the bedroom, shorty isn't always better in a tactical environment. Over the years, I have been issued a variety of SBR's from 10.5 -14.5 and aesthetics aside, my favorites are 11.5 and 14.5. I have an 11.5 with micro RDS and 14.5 with ACOG/RMR. The 11.5 only has an edge in vehicle operations (in my opinion). I run them interchangeably during CQB. Although I don't know which of the CQB methodologies that particular SRT adheres to, I can say the types of missions that would be hampered (slowed) by those 3 extra inches fall into a VERY narrow category.
The 12.5 is a legit compromise for a patrol rifle if you can find a manufacture that suits your needs.
A properly built 11.5 -14.5 upper with quality components will "hang" with the SRT guys.