dual boot vista and w7 on vgn-z21

i have an old vgn-z21wn (european model). it's "running" vista business.
I've often thought of moving to w7 but have been quite daunted by the complexity around the Stamina/Sleep modes and control of brightness etc. that i've read about.

I've looked through the forum threads on installation of w7 on these old vaio-z models:
http://forum.notebookreview.com/sony/426448-vaio-z-windows-7-official-driver-available-now.html
For dual-booting I've been looking at:
How to Dual Boot Windows 7 with XP or Vista

For dual-boot in this particular machine I need some advice ...

According to the sony europe website:
Sony : VAIO VGN-Z21WN/B drivers | Download drivers and updates for VGN-Z21WN/B
Vista requires (and I have installed):
BIOS - R2169M3c
4.26MB, 27/11/2009
BUT
W7 requires:
7UPG_BIOS
1.97MB 23/10/2009.
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As a matter of interest, looking at the page for the "next" vaio model the z31
Sony : VAIO VGN-Z31WN/B drivers | Download drivers and updates for VGN-Z31WN/B
there again there are different requirements at the BIOS level, for Vista:
BIOS - R4041M3c and for W7
BIOS - R4044M3 AND 7UPG_BIOS
Strange (or not) that the Z21 W7 only requires the 7UPG_BIOS
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So my main question, in view of these BIOS requirements, is a dual-boot even possible on the vgn-z21?

As a side question, I'm mainly interested in Vista because of the bundled software, adobe acrobat,photoshop elements etc. Is there any way to get this bundled software into the W7 installation?

All help is greatly appreciated
JC