The Stryker featureed in the game is the basic version without addon armour. If you want to add slat version, look into the "player icon mods" thread, Stirling posted a pack including an icon for such a one.
Tsahal has been using that kind of standoff RPG armor on their APCs for years. Not to mention the chain necklace on the Merkavas; the whole concept derived from the RPG fences used in Vietnam.
So it has to be modelled in the game, on the most modern Israeli M-113 derivates. Look at their HEAT armor rating: either you will have a good starting base for SLAT, or you'll have something else to upgrade!
I guess you could also start with the dozer-blade additional armor: look at the bonus the mine tanks get on frontal HEAT armor.