Wireless instability in new Macbook pro (late 2008) (uniblock model)

Question

I have been experiencing the same kind of instability problems with the wireless connections of the new Macbook pro (late 2008 "unibody") reported in other posts in this section.
My network configuration includes a Time Capsule base station(802.11n (802.11b/g compatible)) and an Airport Express(802.11n) that extends the network and is used mostly for wireless music feeding into sound equipment.
I have been using this network for months with my old MBP (Core Duo,15.4', 2.16 MHz) and it works perfectly. From that notebook iTunes recognizes the Airport express immediately and feeds music without any problems.
I transferred all my configuration to the new Macbook Pro (late 2008 - which is indeed a beautiful piece of hardware, exquisitely designed) and everything works perfectly... except the wireless connection.
It behaves quite unstably. Usually, it is necessary to turn airport off and on several times in the computer to get iTunes to connect to the Airport Express. Even then, the music stream suffers from frequent interruptions and suddenly gets in trouble and looses connection.
While iTunes is trying to reconnect to the Airport Express, usually the internet connection fails altogether, making it necessary to turn airport off and on in the notebook to restart all the wireless connections.
All along, the old MBP wireless connections behave perfectly, proving the problem is in the new Macbook (late 2008) and not in the network.
I have loaded all the firmware and software updates available in the Apple site, and the behaviour improved somewhat with the EFI firmware update 1.6 and SMC firmware update 1.2. I also reset the SMC.
However, the problem is still there and appears now and then seemingly without a pattern.

Answer 1

Folks: *there may be a power/signal issue going on here.* I had a similar problem of my network connection dragging to practically nothing when hooking up my LaCie external drive to the USB port. Please see my post below (link and text)
http://discussions.apple.com/thread.jspa?messageID=9914924#9914924
Folks:
Apple needs to get on this issue fast; after turning off my N mode on my WRT160N Linksys Router, I got my packet speed back up to where it should be... HOWEVER I noticed another problem.
When I hooked up my LaCie external drive (connected via USB), my packets on PING practically stall to nothing. I then eject the external USB drive and re-ping and I get acceptable packet speeds; I re-connect the LaCie external drive to the USB port and my PING crawls to nothing.
There is CLEARLY a correlation between the network speed crawling to nothing while hooking up an external drive; possibly a power sink and/or signal interference on the Airport when hooking up a USB device? (or perhaps even Firewire 800 too?)
I sure hope Apple is reading this one, because this could be a MAJOR issue that needs to be fixed ASAP.