I wanted to ask that i have read some post and i think that i can flash SM G935U firmware in SM G935A and what are the pros and cons ? Other than that what benefits i can avail and what are the lacks i do not?
You might brick the phone - the A is welded shut (software-wise), the U is pretty open. So it's your choice whether to risk it or not. And, of course, you lose the warranty unless you can reflash the A version if you need a warranty repair.