OK since no one else is helping you, i will. Turbo lag is caused byt the time it takes for the exhaust coming out of the engine to start turning the turbo turbines past a speed that will start creating boost, ie actually forcing more air into the engine. The bigger turbo you install, the more power you will get out of your setup (to a point and assuming it is tuned/set upo correctly) but the problem is, the bigger turbo you put on, the longer it will take the turbo to spool up and begin creating boost. So ideally a happy medium is in order: some lag, but not a terrible amount--get a medium sized turbo. Im done for now. search around for more answers.