Well, necroing this thread to talk about the STK-9F, the variant introduced in Rec Guide 24.
And it's a mean one.
Like the Stalker II before it, it uses Hardened Armor to give itself a major boost in durability.
And it's better than the Stalker II in pretty much every other possible way.
Instead of the II's anemic firepower of 2 Extended LRM 10s and 8 medium lasers, the 9F packs the standard array of the classic 3F, but better. The LRM and SRM pods are both Clantech now, as are the large lasers, which are now Clantech for boosted range and damage. Only the quartet of medium lasers remain the same as the original, but they and the large pulses are now tied to a targeting computer for boosted accuracy. A Clan Light Active Probe rounds out the equipment. The low speed makes using the probe tricky, but its armor and firepower does make it good for getting close for dealing with would-be ambushers.
Aside from the speed issue of Hardened armor, the biggest weakness this mech has is heat. A mere 13 DHS cool it, and 26 heat dissipation is not remotely sufficient for that weapon array.