I want to add subs under the rear deck like the M5 has as i want to save my trunk space. If i get a new amp to power the subs will that also power my factoy speakers and head unit? do i have to add an amp to the existing amp? If i can get a new amp to power the exisitng speakers and have inputs for subs this would be a great start. Then upgrade all speakers down the road.
Should i just upgrade the whole system to DSP?
Any advice from someone who has been thorough this would be great,