Not that many differences, off the top of my head :
6 Speed Gearbox, Sony CD System, rear light clusters changed and some chrome round the front grill
Nope that would be the 2005 facelift, the 53 plate one was the 6 speed box with changed clutch/flywheel. New dash/6 disc sony changer + the newer denso satnav as an option Electric passenger seat as standard and think thats about it.
On price, they seem to be holding very well considering the recent tax increases as I got mine with fsh/35k miles 04 plate for 8450 back in march, with a couple of mods too. That 8.5k silver one seems very overpriced as the performance blue holds a small premium over the other colours.