Depends on what bore size you have/had and whether the bores have been scored as a result of the meltdown?, is there enough material left on the block to safely re-use your current bottom end? or are you going to have to start with another block?

Then its a case of whats your 'targeted power' which will determine bore size, piston diameter and what compression is best suited.

Will you need custom made pistons to suit planned diameter/compresson or will off the shelf pistons suffice?

As above have a look at whats available in the states you wont go wrong with JE or CP pistons alternativly look at Mahle pistons for a Cav/Calibra Turbo.

hth's & best of luck on getting your car back on the road