I though I would post this up as Sponge doesn't seem to have done it already.
A couple of days ago the shifter on his G25 started going funny, not recognising shifts (1st, 2nd and 3rd gear were completely broken for a little while) He managed to fix it, turns out the drivers had corrupted sometime while the computer wasn't in use.
While he was having a spazz fit at it, he contacted Logitech customer support with the problem, they emailed him back very quickly with a the gift of a 25% discount code on a brand new G27, as the G25 is no longer in production.
Keen to take up the offer, he emailed them back asking if the code would be valid for use in a couple of months when he was willing to upgrade to a new wheel, to which the responded by giving him a 50% discount code if he would use it in the next month.
So, if anyone who has a G25 is having any problems with it, contact Logitech's customer support! He bought his G27 yesterday, Amazon retail price is £332, Logitech retail price is £250. Sponge got his, a brand new G27, for £125. I reckon that's the bargain of the year.