Was wondering which would be better to use as the outlet (rena xp2 canister filter ) the spraybar or power jet nozzle?? Or does it matter??

The nozzle is good to get flow in the tank and the spray bar is good for those fish that don't like a lot of flow.
So it all depends on the fish in the tank.

im leaning towards the nozzle but if it is placed to low towards the bottom cant it disrupt the sand?

It surely will disrupt sand, and blow it around quite a bit. How will you plumb your outflow that low?

I prefer to use the nozzle because I have a thing about visible equipment in my tanks, and if the fish don't care for a lot of flow then I point the nozzle into the back corner, or otherwise aim it at glass to disperse the direct flow.

I tend to aim them so it flows diagonally down the length of the tank, by the time it reaches the bottom it is but a very gentle flow.

like Fern said it depends on the fish. a lake fish will want still water while a stream fish wants quite a bit of movement

I like the nozzle over the spray bar...couple of reasons.
1. Nozzle less noticable than the spray bar
2. I seem to have less water evaporation with the nozzle
3. It is easier to feed my fish which like the food in one area rather than quickly dispersing throughout the tank

Just my $.02

I use the spray bar in one tank. my flowerhorn tank, they need some serious surface movement for gas exchange, So I have the spray set to go along the surface of the water.

What fish are in your tank and what size tank, The more info the better the answers.

firemouths is mainly what is in the tank