Ok when i land and i have flaps to full and the breaks are on and reverse thrust is on too. do i actually need to have spoilers deployed aswell if i know im going to stop before the end of the runway?
The Spoilers deployed on ground don't help the aircraft to stop. They prevent the aircraft to lift. Now, spoilers deployed in the air help the aircraft to slow down.
Actually the stopping power of spoilers on the ground is quite small; what they really do is interrupt the flow of air over the wing, increasing drag and reducing lift.
They are used to slow down while in flight, but their primary function on the ground is to "dump" lift.
So to answer your question, YES. Always deploy spoilers. On real life, many times due to noise restriction or to increase engine life, pilots will not deploy thrust reversers but they will always use spoilers.
Spoilers are integral to getting weight on the wheels so the brakes can do their jobs. Not deploying spoilers is dangerous 'cuz the plane still wants to be a plane, and planes want to fly, not land, if they are stowed.
don't forget that you can arm them on the approach - shift & / - so that they will automatically deploy on touchdown.