s430 vs s500
 

So my other transportation is a lease and i am forced to be under a certain amount of miles when the lease is terminated. This lead me to purchase another car a used s430. I like the car , and im even thinking about leasing a 500 when the other lease is up , so here's my question's.
i currently drive a s430 whats the difference with that and a s500? is there a large price difference? options?