Currently I have a turbocharged Kawasaki ZX10R engine, Tial 38mm external wastegate with an 8psi spring and a manual boost controller to give me my upper boost setting, low boost 8psi and high boost 15psi.

During a recent mapping session we found that the boost controller wasn't controlling boost as it should, so I'm planning on fitting an electronic boost controller (particularly like the look of the Turbosmart E-Boost Street) and a smaller wastegate spring.

Doing the above would give me 3 boost settings...

1) 4psi from the wastegate spring
2) 8psi low boost using the controller
3) 15psi high boost using the controller

Can you go too small with the wastegate spring in comparison to the maximum boost you wish to run? is there an ideal or maximum ratio between the two? or does it make no difference?