Catcam 403's

Although Maxi are 3 ring pistons you'll want to check what material they are, depending on if your car is a daily or track only this can be important to consider.
If it's track only it matters less, generally 2618 is what you'll want on track/race only, they are the most resistant to abuse but because of the purer alloy content they expand more and therefore need a bigger gapping to the bore. This means they wear much faster on daily driven cars.
If your car is a daily you'll want 4032 which has a higher silicone content and so expands less, resulting in tighter tolerances in the gapping and therefore wear less in a daily use (frequent/cold starts etc).

The PEC pistons are designed and manufactured by Supertec in the UK, I'm told there are a nice piston buy a couple of places and the quality of the machining is high, better than Wossner for example. They're 4032 so perfect in a daily.