Boost controllers differ from bleed valves in that they control the boost electronicly.

Nothing wrong with bleed valves if they are used/fitted by a pro whilst having your car set up.

There will be a reason why your car is running the boost it is, whilst setting your car up(optimising the power) The weakest link in your spec will to an extent govern the boost and timeing that your car can run.

Dont go messing with your bleed valve. You'll more than likely dammage your engine turbo etc.