I think the second GXP picture is a concept, I've never seen it ever. LEDs can be found super cheap on ebay and so can those tail lights.
04-08 Pontiac Grand Prix Black LED Tail Lights Left Right Rear Lamps Assembly | eBay
And yes, they are worth it, I love mine.

And go with some SPO grilles. The projector headlights are crap unless you retrofit them yourself