Hi all, I am new to car audio but looking to do a subwoofer install (wtih some help from my friends)...I recently visited a car audio store to get information and look at the subs and amps available. After explaining a little about my preferences, the employee who assisted me said that my Volvo has a separate amplifier built in, and if he were to do the install (of the new head unit, the sub, amplifier, and speakers), he would need to circumvent this amplifier and wire around it. Now, I have done a little bit of research into this, and I have not found anything about an amplifier separate from the 4x25w amp in the premium head unit that came with the GLT model. Any ideas?
Additionally, if there are any experienced audiophiles out there, I am having a dilemma. I was set on getting a Focal Access 27 Lux (11") sub, which produces 250 RMS (small on power, but sounded good at the audio shop) and comes in its own custom enclosure. I could get this for about $295 and then a 5-channel amp to run the sub and then the speakers. On the other hand, my friend is selling his Audiobahn Alum10x for $150, and this sub produces 800w RMS (so much difference in terms of power!). I would then have to get a class-D amp, and I guess I could run the speakers off the new Pioneer head unit. Then I would also need to construct an enclosure or buy a premade one. However, I have heard that Volvo sedan trunks are very soundproof. I was leaning more towards the Focal but hoping that it would have enough go power to get the bass really going (not really sure how much power I need, but I am focusing on sound quality, not SPL). Any suggestions here? Or any other routes you think I am overlooking but would be a better choice? I am trying to not have to spend excessive amounts of money, and I thought I knew what I wanted, but this situation is now truly confusing to me. Not sure which path to take. Any advice would be ever so helpful!
One last thing...anyone know the speaker dimensions in the '95 850 GLT? Thanks!

Nora