standard sound in the e46 is total crap...I had one
hk sound in the e46 is very very nice, but I can't say perfect... I have
one actually...
(it comes from the bass that are "gloudy" ? because the subs are at the
back and too isolated from the cabin. you can't really enhance the other
speakers...
but I read some article (dont remember where) saying that to really
enhance the hk sound system you would have to pay some $5000... and
rethink where the speakers are located...
so I dont think your $100 system is even worth the try...
(it would have been if you had the standard x5 sound system...)

Thank you all for your help.

To answer some of your questions:
1] Typo (sorry) - "Bostons" should be "Boston" or "Boston Accoustics".
2] I didn't know that the 10-speaker system is a HK system. I'm familiar
with the crisp clear Bostons Accoustics sound systems. No, I haven't
listened to the sound in the car yet. It's been purchased at A BMW dealer
with the help of a friend of mine who has his own non-BMW shop. The sound
in my E46 is worthless.
3] The X5 will be shipped to the Netherlands in Europe and was wondering
how much it would cost to replace the speakers in the US and over here in
Europe.
4] Just found out that "Crutchfield" recommends the S55 and SX55 for the
X5.After Price break/rebate the SX55 would cost me $99.99.

Hi all,

I have purchased an E53 X5 (2005) which will be delivered next week. It has
a 10-speaker HiFi system but would like to replace these with "Boston
speakers".

My questions are:
1] Does anyone know which Bostons speakers will fit
2] Any idea how much this will cost

Thank you for your help.
Sonny