mustangsel

Hey guys I was at a local mustang shop getting some work done to my buddies car other day and I got talking to the owner of the shop. He was telling me that the only other thing I can do to my car (04' Mach 1) is putting a Lightning MAF on it. I already have every bolt on for her. Is this true? I thought if you put a bigger maf then you have to put bigger injectors, but he said no. If this is true then how much power will I get? Thanks guys