PIAA have in-line resistors, yes they are "plug an play" but these still have resistors.
What do you think the round bit is in the middle?
Ahhh... i haven't looked at the PIAA's in great detail, i see what you mean now. if only i could find £80 lying about the street now... or a few lucky scratchcards!
What size resistors would i need for these LEDS i have now does anyone know?