You'd need more than just a rod job for that power. Full rebuild of the engine, cylinder head and transmission. On top of that, better brakes, twin plate clutch, 1000cc injectors, uprated fuel lines, regulator, a well spec'd turbo and manifold with 3" piping oh yeh, and to map it on either SD or an aftermarket ecu. It really depends on your budget, but done properly it will cost between £15-20k
A rod conversion on its own is around the 2K mark.
Bust as Steve has stated 600bhp is serious money.
Not sure what mods you currently have but rod con + turbo I suggest would get you to around the 475-500bhp mark but running that power it's wise to have bigger brakes, better clutch/transmisson, injectors etc too
Yh rods alone won't get you there without it going bang and puttin one of ya nice new rods through the block. You would be better off sourcing the parts uprated and when you got em All together take it along to get put together. Or just get it all done in one faol swoop which will cost a few k