Assuming you have an ecotec or an L67 engine, then the parts that would be suitable are shown in the links below,

Valve Springs http://www.maceengineering.com.au/epages/shop.sf/en_AU?ObjectID=1469582

Please note that these require retainers to suit as shown in the link below http://www.maceengineering.com.au/epages/shop.sf/en_AU?ObjectID=1469377

Camshafts to suit turbo application http://www.maceengineering.com.au/epages/shop.sf/en_AU/?ObjectPath=/Shops/mace/Products/CAM609/SubProducts/CAM609

Please note that either the Stage 2 or Stage 3 cam would require valve stem seals to suit, due to the additional clearance they give between the retainer.

These seals are available in the link below http://www.maceengineering.com.au/epages/shop.sf/en_AU?ObjectID=1469378