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