as far as im aware the new catcam 743's are the best ones to get, they are the latest design from catcams (£300), you will also need to factor in labour for fitting the cams, and the labour for having the cam timing and ecu map adjsuted on a rolling road to get its full potential (around £500)
obviosuly fitting some sort of induction kit/panel filter and a 4 branch manifold with a de-catted exhaust would be needed otherwie fitting cams would be a waste of money (>£400)
also a good time to replace your cambelt and water pump (>£100)
if youve got some money to burn then take the head off have it skimmed, cleaned, port and polished, valve seats re cut, new stem seals, new cam seals etc (£700+), headgasket kit and bolts (£120)
on the cheap you could just buy some second hand cams fit them and leave them un mapped and on std timing marks could be done for £200 or up to between £1-2k if doing everything i mentioned