IMHO that's a good vintage to buy. Taken the big depreciation and later than the very early one's that seem prone to broken rear springs.
There are no real worries on the 3.0i auto
I'd just be checking for damage at the front on the lower edge of the spoiler and undertray. Very vulnerable, along with stone chips on the nose
Check hood is in good condition - very expensive to replace.
Seems from recent buyers experience that there are a lot of accident damage examples around so be very fussy on any respray, panel gaps, etc.
Get one with the sport button - big difference
Xenon headlamps are almost essentail as halogen are poor
Accessories are the real differentiator at that age so decide what you want from Sat Nav, to ///M seats, heated seats, upgraded stereo to the style of alloys, etc. If you can get a hardtop you'll be glad come Winter for both comfort and style and they're worth £900+ come Autumn.
FSH is nice to have as you'll be out of any warranty by that age
There are many around so if in doubt walk away.....
Good luck
Good luck