This article from Strategy Page is primarily about the conversion of heavy brigades to Stryker brigades, but also provides a nice overview of the manpower and equipment that comprise a SBCT.
SBCT’s comprise 3 Stryker infantry battalions, each having 36 Stryker vehicles distributed among 3 companies (12 each). Nine Stryker Mobile Gun vehicles, mounting 105 mm guns are there for anti-tank and infantry support roles. Nine Strykers, equipped with guided anti-tank missiles, form an anti-tank company. There’s also an artillery battalion with 18 towed 155mm Howitzers, a support units (usually company size) for Medical, Maintenance and Distribution, Headquarters, Signal, and Engineers. There is Reconnaissance squadron comprised of 42 vehicles. Total brigade manpower is 3,900 troops.