I would say obtaining 300bhp and a genuine 300bhp will take some money mate.

Most items will need uprating, box, clutch, engine internals etc etc.

I would get the car RR'd and see how healthy the lump is, then look to what power you can achieve on what budget and go from there.

As for winding the boost up, i would say don't fek about unless you know what your doing, otherwise there will be a loud bang, and recovery truck and a poorly wallet.

You would be suprised what a well set up car can pull like on 200bhp, again a genuine 200bhp, not someone who has stuck a 195 chip in and claims it to be ruuning that power.

The other thing to consider, is how useable you want it, running big power can lead to a car that is a pig to drive normally and can suffer over heating issues and constant breakage.

If you want bigger power, sell up and buy a cossie or similar that have a bigger more powerful block from the get go.