Boost droping!

Ok car ran 15psi on ct26 for a good 3 months no problems what so ever! Then as of this month it hits 15psi and drops to 11psi in higher rpms. I have all new plugs, wires, cap, rotor, etc. i got all that stuff. So im guessing that its a leak in the lines or possibly the blitz bov which has had its problems since i got it, also i heard they are crap. Because the thing is when i take the boost controller off i run 10psi all the way to redline with out it tapering off. Any other possibilites of what it might be ? any help is greatly appreciated.

Most problems in the running condition of MR2s comes from ignition pieces or BOVs.

You have a freash ignition already.
I'll give you one guess what I am going to recommend getting rid of :D