1.8T 20V cam timing step changes

[sambb]

Ive fitted the 1.8T 20V BJX in my Polo with Cat Cams adjustable cam timing pulley. The engine is internally stock and is broadly in stage 2 guise as far as hardware goes. I'm going to experiment with advancing the cam timing and was hoping to hear from people who have done the same - I'm curious to hear what step changes bring results (if any) on an engine that is still fed by a K03s, what the limits are ie surely I should be able to test to at least 3 degrees advanced on the cams yeah?
thanks for any help
sam