If you want faster spool up you need to add more fuel. If you put a bigger turbo on with the same fuel it will take longer to light. If your looking for a great combo, try stage 2 injectors, and a gt38 ball bearing turbo, get your chip reburned to take into consideration the upgraded injectors and then start thinking about the fuel system. DI or ITP can help you out with that. Don't just throw stuff at it and hope for the best. Think about where you want the rig to end up at. Think about the COMBINATION you want, that's what makes a great runnin' rig.