The TC-2's seeker head is based on Motorola-Raytheon design, initially a competitor to the AIM-120 contract, which was later won by Hughes. CSIST is reported to have purchased 200 TC-2 seeker head "kits" from Raytheon. This led to speculation that the ROCAF would have no more than 200 TC-2's in its inventory.
On March 17, 2004, Jane's Defense Weekly reported that CSIST had produced an air-launched anti-radiation (ARM) missile, named Tien Chien IIA (TC-2A). The TC-2A is reported to have a new seeker head and guidance package, possibly with dual-mode passive RF and IR sensors, and an improved extended-range rocket motor. The updated missile, with its new seeker head, indicates that CSIST's TC-2/TC-2A production is not limited to the original Raytheon order.