That's a big tank,so alot of circulation will be needed to eliminate dead spots.So you will need at least four powerheads.
My favorite is the haggen 402's.They are big,powerfull,last a lifetime,and are fully adjustable...Place two in each rear corner,one on top of the other with the toptwopointing to the center of the front glass.These topones should also create a ripple across the waters surface for added airation...
The other two(bottom ones) can be pointed across the tank to the opposite front corners.
After they are in place the rock work can be adjusted to hide them as needed.
For heaters,you would be best off with two or three low powered ones instead of one big one.
This is for several reasons.
#1,if the one big one ever was to stick in the on position,your tank will quickly overheat and kill everything in it.By using two or three smaller ones,when one malfunctions the other two will shut off as the temp rises,this one small heater will take quiteawhile to overheat your tank.Thus buying you valuable time to catch the problem..
#2,Multiple heaters will eliminate cold/hot spots in the tank.
Placement depends on a couple things.What kind of filteration do you have???If you are running a sump,this is the best place to put at least one of them...Then put the others in the corners behind the powerheads...