3"straight hose
i dont know why you're worrying about the maf hose when you really need to replace that pos cracking hose from the turbo to the intercooler
It looks like the hose on your new maf pipe is a 3in - 4in adapter hose. Like pacecarta said, 3in straight hose. One thing at a time, replace the stock maf hose so you're not sucking dirt in, then work on the rest.