Yes what he has heard is correct, you have to chop a bit out of the linkage to change the gearing/position of the linkage if using an F28, thats what I did on my mates recently.

www.vauxsport.com is certainly the best place to get details, there is an awesome thread on there with everything you could ever want to know about XE'ing a corsa:

http://www.vauxhall-sport-forum.com/...orsa-t106.html