The system is effectively running three amplifiers.
The fronts are powered by one pair of channels full range with passive cross overs at 93w rms 2ohm load
The rears are run by another pair of channels full range with low frequencies removed running 63w rms 4 ohm load
The sub woofer is powered by a mono amplifier giving 562w rms. at a 2 ohm load.
The original head unit, and boot floor has been retained and the tweeter panels are cheaply replaced. The car has been installed with the brief that I want to return it to original. New speaker cable has been run in so that no splicing of cables is required and or kept to a minimum.
The amps could of been hidden, but are very attractive units and I felt they should be showed off. I realise it won't be to all taste, but without exception the proof is in the hearing and all who have heard the system have been amazed. This includes a sound engineer.
Take the point of corner subwoofers, but they take up boot space which means I can't get my golf clubs in. I think you will be surprised by the quality and tightness of the bass response which is what I look for. If you want bass to be heard a mile away then you want a different solution and probable a different vehicle that's less well sealed. I have the sub ticking over and it's plenty loud enough. It also drops down to frequencies I can only feel.
An active set up was looked at but we felt at the time this was the right way forward as to change it round is possible, but ideally would require another amplifier to keep entire system powered.
E90 330i SE Auto Graphite Grey Metalic