I just bought a cover from California car cover. I keep my car inside so I bought the dust stop, but they make other types that are more weather resistant for outside storage. The cover they furnished is for the convertable as the roof lines are similar. Mine fits perfectly.
I really like the Covercraft Weathershield. Its very light and compact and yet very tough. It only need to be tied on for really strong winds. It can be washed and dried in home washers and dryers. I've had mine for 6 months now and it doesn't show any wear despite numerous washings. To prevent scratches keep the cover and the car clean. Wash both at the same time. Beware that some covers specifically indicate they are to be washed only by hand.
I have the GM cover for the corvette C5 series. It fits the Z06 well and comes with a grommet kit to allow for the fixed Z06 radio antenna. It has the words Corvette printed on the front. It is heavy duty and the fit is good and not too tight - since I keep the car garaged the weather proof qualities are not an issue- protection from moving people and loose objects are the issue.
I also received as a gift a California Car Covers version for the Z06. It fit is a bit tighter and is quite a bit lighter than the GM cover and might be better for traveling because it is lighter and packs tighter - there was no grommet kit for the antenna just directions to cut a hole - not a great solution! they should have included a plastic grommet kit (15 cents max). For now the Z sits under the GM version cover in the garage.
Try Ecklers, on line or give them a call and they will send you a free catalog in no time flat!
They carry many different types from several different manufactures and at reasonable prices compared to several of the other big name Vette accessories dealers (I shopped around)
I got the Dust Top since it stays in the garage all the time and the only protection I need is from dust
from Mid America good for the inside and outside...one cover does it all, also the Noah cover is very good. Both of these covers are under $150.00. Never dry them in a clothes dryer because they will shrink. Best to wash them on the car, and let them air dry there also. Do the other side the same way..reversed on the car.