Hi Laliii. I have reluctantly sold my Calibra so do not frequent the web site any more. Did you find the cams you want? I have 3 pairs of G cams!
I beleive, but stand to be corrected, that Courtney Tuners take G cams as 'blanks' when u buy their own performance cams! As I ran a Vectra GSI at the same time, (sold as well)! I know that the 2.5 with A cams was rated at 178 bhp. The GSI with G cams was rated at 192 bhp, but the same engine as the calibra, (not taking into account the plenum differences).
So if the G cams give you 14 bhp over the A, and the Courtney cams give you 18 bhp over the G, that is a massive 32 bhp over standard.
I am not an expert so if I get over-ruled so be it. But when I saw your question I had to reply.
So, I still own 6 G cams! Who wants to put them to good use?
Cheers