I am not sure the extra beam range (8%), sensor range (6%) or crit chance for lasers is worth five tons. Otherwise, create hardpoints for this type of build. Decent speed and arm lasers and good high missile mounts. _ Trade a ton of ammo for a Clan Active Probe or another heat sink if you like. ps - check the jj in the title.
the TC is for the Targeting Time Boost the faster you lock a target, then faster you get to shoot em thanks for the headsup on the titles!
The targeting computer speeds up the time to get the damage information for the target mech on the paper doll (yellow, orange, red). It does not help with faster missile locks in any way, unless PGI has mis-coded something again.
This As far as I can remember, only TAG and NARC speeds up lock on acquirement (I'm sure about TAG, I'm not completely sure about NARC, I remember it was nerfed some way)
With the latest changes, Tag/Narc help others that do not have line of sight get the benefits of having LOS. Faster lock and less missile spread. Tag still tightens up the spread of the missiles a bit and helps light up enemy ECM mechs for targeting which is nice. If you visually see an enemy ECM mech, you should be able to hold the reticle on it and get a lock eventually. But don't take our word for it. Go ahead and test things out both ways and see if you see a difference. There is a history of things like Artemis helping in ways that were not intended by PGI.