are spark plug wires better if they are thicker.
whats the diffrence between 10.2 and stock 7mm

 

Not necessarily...thickness doesn't increase spark energy, it's just extra material to try to suppress EMI. Alot of those aftermarket wires perform the same or maybe worse than new stock ones and sell them on the gimmick that thickness = higher performance. The reality is that while some wires might be more efficient at transferring electricity, no wires actually "make" horsepower.
I am partial to Magnecor wires, the KV85 (8.5mm) is a nice street wire, you'll probably never have to replace them unless you abuse them somehow. Find their site and read the wire tech section, it's informative.