i had autozone scan the car and they found no codes. it peaks at 15psi holds at 13psi until 4500rpms then drops to 10psi and lower. Could my having the DV on backwards for a couple weeks killed my turbo?

 

no it wouldnt kill it. The dv will work the same either way its installed. Your boost #'s went up?I would replace the vac line (skinny one)that goes out the top of the dv accross the front of the engine and down under the intake manifold. If its leaking that will cause the dv to not hold boost well.