Don't expect any of the aftermarket bumpers to fir without any work ... That said, the Lingenfelter bumper is about the biggest POS I have ever seen, it had lots of pinholes and even cavities under the gelcoat. Now its all fixed but the quality is just so poor it should have never left their shop like this.
Ecklers fiberglass is usually very good quality, so is Vanacor's stuff.
I have seen one Z06 replica bumper for the front that fits the stock C6 fenders, i was considering buying it, looked really good. Too bad I don't know who sells it, thonk I saw it offered on one of the forums...