My Sapphire Cos 4x4 will be getting the head pulled off soon for a rebuild and i've got a few ideas in mind to improve the spec and hope for as near as makes no difference to 400bhp and a nice healthy torque curve to go with it so here's my list, all comments and advice on different specs is much appreciated.

Port and polish
BD14 inlet
Double valve springs
T34.48 ( being sent for rebuid )
Vernier Pulleys
Alcon 6 paddle clutch
3 Bar Map
Group A Headgasket
And finally a nice live mapping session.

Just a little question about fitting the BD14, would this be ok with just the port and polish and the double valve springs, or will further work be required? Also what size Siemens injectors would i need? I was told 55's but not sure. Thanks in advance