What bhp can be had?

[Eeyore]

£50 will see 125hp on a hdi.
a bit of a tune on a dturbo will see 120hp i believe. add a bosch pump to that for £150 and you can run 135hp and veg.

Then after that with both you need to install an FMIC which is anywhere between £100 to £300.

Then you can start running 150hp on the hdi and probably 160hp on the dturbo.

After that its bigger turbo, custom manifolds, custom maps in the case of the hdi.