I personally don't think it is your ECU, but probabaly either the Venom 400, the connections, or posibly the MAP sensor. I would do what others suggested and totally remove the Venom, not just turn it off. For this part, it is a simple as disconnecting it from the TPS and MAP sensor wires. Then reset the ECU again as see what happens. While it is conceivable that your ECU just happend to go bad after installing the Venom, the Venom itself would not be a likely cause of the ECU failure, unless the Venom 400 module itself was malfunctioning and bad. All the Venom 400 does is vary the input volatage from the MAP to the ECU, but within the OEM range of 0V to 5V.
As for used ECUs, I would check all the online salvage sites, as the usually have a couple of G2 ECUs for less than $200.
Be sure to get the one for your car. In other words, you can use the same ECU for the 91-95 L and LS Sedans. The 91-92 Coupes use the same ECU. The 93-95 LS Coupes use the same. The 93-95 L Coupes. The 94-95 GS Sedan, and so forth.