About spring pressure , why not configure the turbo to power up sooner instead of getting seat pressure out the ying yang ? It'll be more fun riding it with quicker spoolup anyway . Unless you're going for track use or king of the dyno , I see no reason to have to turn the motor to 10,500+ rpm .
Turn it less and the HD springs are more than enough . In fact , for my money , I'd leave the stock exhaust springs in it if you get it to make peak power around 9500 , shifting at ~9900 or so in full race mode , less when all the marbles are not being bet .
It'll be better on the valve train , better on the bearings etc . Win-win if you ask me .
Oh , btw , I'm sure you've told me before , but what have you done engine wise ? 1100 or 1200 ?