looking at engine mods for my mk5 1.4 16v..

Current mods:
-Pipercross panel filter
-Scorpion cat back exhaust with mani-cat chopped out

Mods thinking about:
-Cams - http://www.lmfvauxhall.co.uk/Cat-Cam...4-1.6-1.8.html will they fit for one question? if so, what gains am i looking at?

-Air intake - http://www.regal-shop.co.uk/vauxhall...r_Intakes.html will i get much gain from this over my pipercross panel filter?

-inlet manifold - regal supply a inlet manifold for £870 which is mad money, what benefits do you get?

All help appreciated! any other ideas welcome