Ideally if you want more that say 220 bhp (which is the limit without spending so much, that it would be cheaper to buy a cossie engine) you would need,

T3 and manifold.
Forged Low comp pistons (around £600 as no one stocks them).

And even then Ratty & I reckon the 8v head will onlt flow to get you to about 260ish.

To get 220 on standard compression you would need MBE or Fiesta RS turbo management with a set of beige injectors and the loom and also modfy the engine sensors, plus someone to set it up.

Only option really is the low boost set up and a whiff of gas.

If not ditch the lot and throw your money at the cossie lump.

Remember cams are about £200 for the twinky and it will only rev to 6250rpm

Hope this helps