<E39> 540ia audio amp and speaker upgrade

["Willy M. Lee" <Willy.Lee@xxxxxx>]

Wondering if anyone has done an audio system upgrade to an E39 base audio system...

I was thinking of changing out the front speaker drivers and installing a new amplifier, but one installer said it would be very expensive and difficult to do.  He said that the passive crossovers are built into the factory BMW amp and not in the front doors or x-overed at the speakers.  I was hoping to swap out the stock amp w/ a Soundstream amp and use some high-level to line-level converters to feed the amp. Also, has anyone tried to mount aftermarket drivers in the factory front door placements (and what sort of drivers did you choose to replace with) and encountered any difficulties? 

Any suggestions as to improving low bass response?  I have always opted for a 8-10" sub w/ enclosure in the past, but in the E39 I plan to carry some golf clubs and don't want to clutter up the trunk or ruin the "factor" look.  The small 4x9 subs in the E49 w/ Harmon-Kardon upgrade seems like a decent compromise, someone mentioned that some aftermarket car audio company (same one that makes DynaMat??) makes some acoustic membrane that you mount between a freeair subwoofer and the rear deck that fools the subwoofer into thinking that it is firing through an enclosure...anyone used this method before w/ good results?

thanks, please cc my email account,
Willy.lee@domain.elided

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