which corvette is better a C5 or a Z06 and what are the main differences?

 

C5 denotes which generation the Corvette is...C4, C5, C6, etc. Just like 3rd Gen. and 4th Gen. Camaro's. ZO6 is an option code just like Z28.
For the C5 Corvettes the ZO6 only came with the hard top and manual trans. It was not available in the coupe or convert. It was lighter and had more hp.

The C6, ZO6 has so many different parts that it is almost it's own model. It's much lighter and has almost 100 more hp. There is no hard top C6 so it comes as a coupe, but still only with the manual trans.