Ford Essex V6 advice!

[DAKOTAstorm]

I am about to get an engine reconditioning and the garage have come back with some possible options I could add to this, some of which I simply don't know. Can anyone help explain in simple terms, what effect the following will have on the engine?

Performance Camshaft profile
Gas flow Inlet Manifold and match to ports in Heads
Roller tipped rockers
Uprated valve springs

Any light shed on the above will be appreciated greatly!

[DAKOTAstorm]

Thanks for all the links and advice, in the end budget determined the build, heads being too pricey a lot of stuff was not needed as the standard stuff was deemed to be able to cope, the engine is getting a full recondition with the majority of moving parts replaced for better and the Gas flow Inlet Manifold and match to ports in Heads with a lightened fly wheel are the options I chose to make the engine breathe and rev more freely. The engine is for a TVR 3000M and is the original, which is why I didn't want to replace it with something more powerful or japanese! thanks guys!