The load doesn't change whether the amp is bridged or not - 2 ohms is 2 ohms. However - many amps that are 2-ohm stable will specify 4 ohm stable in bridged mode, which I think is what you're trying to say. This is why I asked for more detial on the amp - regular 2 channel amp or a true mono amp.
I am not here to get into an argument but I will have to disagree. It does make a difference "bridging a stereo amp or using a mono block amp". Yes "an ohm is an ohm" however what we are looking at is that if you bridge a stereo amp, each channel shares the load. Therefore the single output of the amp in a bridged mode would see 1/2 the load. So a 2 ohm measured load ( 2-- 4 ohm subs in parallel) at the amp will actually cause the amp to run at a 1 ohm load, causing extra heat, early clipping of the amp, over driving of the power supply in the amp etc. All causing possible damage to the amp and (or) burning up ( blowing) of the sub and the $$$$ that you have just spent.
As for having a "fan" on the amp, that would only be like putting a band aid on a gash that really needs stitches. The fan will help keep the electronics cool but it will not help the over driving of the amp. You WILL still have trouble.
If you still do not believe what I say I ask that you look up any of the Technical Help lines for any of the major players of Auto Sound equipment ( JL Audio, Rockford Fosgate, MTX etc) and speak to them about it.