Well thats exactly whats expected alf from a big turbo.. ur suffering slower 60ft coz ur not used to launching a big turbo (im only assuming) which if u leave the line well will allow for a better run.. mid range ie till 330ft is coz the turbo does not have enough boost to get it "alive"..
top end impoved coz obiously the t3 has a bigger ass & flows more top end.. i would try 16psi, & see how ur runs do.. id say ud go much better..
kon