I wasn't comfortable mentioning you by name. Seems gossipy to me.
Any idea how the factory HU reduces the bass output? Built in crossover of some sort?
NP - on the shaker they filter it and redirect the lows to the subamp. the other 4 signals are passed on to a different amp i believe. On the base (and this is just my best guess) the speakers are full range and there 'may' be some sort of level control to prevent 'clipping' the amp. Several members have posted about using LOCs, personaly I have never used one. If you find the volume / sound accepable using the factory head unit, you could try to add the basslink. If you find the volume / sound unaccepable using the factory head unit, you could try add an amp with high level inputs (saving some budget), the nth degree would be LOC's in to a sound processor, into multiple amps (but that WILL cost).
good luck & have fun (after all that's what these cars are all about).