This is the JL one, I assume specs are similiar.With the amp I'm looking at it would only be about 75watts to each of the 4 channels. Would really like to know the specs on that factory sub. I don't think that will harm the factory sub and will just provide bass fill, not looking for tub ratling thump from it.
No need for a 4 channel. OP could do a Monoblock at 2 or 8 ohms.If your amp you are looking at is 75wx4 at 4ohms it will likely be 140-150wx4 at 2ohms, assume it’s 2ohm stable. Way too high for the sub, but with the gains turned way down it would definitely sound far better than the stock 45Wx4.