Read somewhere that the GSR intake springs are actually a little stiffer than the ITR because of the heavier valves. Is this true? Can someone confirm this??

I have also heard that GSR intake springs are the same as ITR exhaust springs? I'm confused now.

Anyways, i plan to run skunk2 stage 1 cams in my GSR and i wanted to know if it would be ok to have my redline set at 9000 rpm with this valvetrain in addtion to getting ti-retainers.