You will probably be able to run a k04 on calibra injectors, VR6 MAF and a GOOD FMIC.
Forged rods are £285 in the UK from backdraft.
Pistons are ok, but id change them personally, better compression ration. £380 shipped from US for JE's minus import tax.
Then supertech valvetrain. Cheapest i can find without tappets is £680 from holland.
Theres nothing cheap about building a reliable engine for big power.