fountain guys.
 

Are the bottoms the same on lightings and executioners.
How fast is a 42 executioner with 2 x 525s stag.

Depends on the year. The 42X will run 82-84 light with 525's. Around 80-82 everyday.

I have an "05 42 EX with staggard 525's with Xr drives. In "05 they are the same bottom. As Fountain 40 said the boat will run 82 all day long and 83-86 under the right conditions. I am running a pair of labbed 30P Maximus and there is some room for improvement on the props. I only get about 5100 rpm out of them, but they do run well out of the hole and thru mid-range. I have run 28P stock Max's and they are a better all around prop but tend to be on the rev limiter Great boat, runs smooth, level, and well in all conditions.